avrdude - Man Page

This option specifies the MCU connected to the programmer. The MCU descriptions are read from the config file. To see a list of currently supported MCUs use ? as partno, which will print the part ids and official part names. In connection with -v, this will also print a list of variant part names followed by an optional colon, the package code and some absolute maximum ratings. The part id, their official part name, any of the full variant part names or their initial part up to a dash can be used to specify a part with the -p option. If -p ? is specified with a specific programmer, see -c below, then only those parts are output that the programmer expects to be able to handle, together with the programming interface(s) that can be used in that combination. In reality there can be deviations from this list, particularly if programming is directly via a bootloader.

The following parts need special attention:

AT90S1200

The ISP programming protocol of the AT90S1200 differs in subtle ways from that of other AVRs. Thus, not all programmers support this device. Known to work are all direct bitbang programmers, and all programmers talking the STK500v2 protocol.

AT90S2343

The AT90S2323 and ATtiny22 use the same algorithm.

ATmega2560, ATmega2561

Flash addressing above 128 KB is not supported by all programming hardware. Known to work are jtag2, stk500v2, and bit-bang programmers.

ATtiny11

The ATtiny11 can only be programmed in high-voltage serial mode.

Run developer options for MCUs that are matched by wildcard. Whilst their main use is for developers some flags can be of utility for users, e.g., avrdude -p m328p/S outputs AVRDUDE's understanding of ATmega328P MCU properties; for more information run avrdude -p x/h.

Override the RS-232 connection baud rate specified in the respective programmer's entry of the configuration file or defined by the default_baudrate entry in your user configuration file ${HOME}/.config/avrdude/avrdude.rc or ${HOME}/.avrduderc if no baudrate was defined for this programmer.

Opens the serial port at 1200 baud and immediately closes it, waits 400 ms for each -r on the command line and then establishes communication with the programmer. This is commonly known as a "1200bps touch", and is used to trigger programming mode for certain boards like Arduino Leonardo, Arduino Micro/Pro Micro and the Arduino Nano Every. Longer waits, and therefore multiple -r options, are sometimes needed for slower, less powerful hosts.

Specify the bit clock period for the JTAG, PDI, TPI, UPDI, or ISP interface. The value is a floating-point number in microseconds. Alternatively, the value might be suffixed with "Hz", "kHz" or "MHz" in order to specify the bit clock frequency rather than a period. Some programmers default their bit clock value to a 1 microsecond bit clock period, suitable for target MCUs running at 4 MHz clock and above. Slower MCUs need a correspondingly higher bit clock period. Some programmers reset their bit clock value to the default value when the programming software signs off, whilst others store the last used bit clock value. It is recommended to always specify the bit clock if read/write speed is important. You can use the 'default_bitclock' keyword in your ${HOME}/.config/avrdude/avrdude.rc or ${HOME}/.avrduderc file to assign a default value to keep from having to specify this option on every invocation.

Note that some official Microchip programmers store the bitclock setting and will continue to use it until a different value is provided. This applies to "2nd gen" programmers (AVRISPmkII, AVR Dragon, JTAG ICE mkII, STK600) and "3rd gen"programmers (JTAGICE3, Atmel ICE, Power Debugger). "4th gen" programmers (PICkit 4, MPLAB SNAP) will store the last user-specified bitclock until the programmer is disconnected from the computer.

Use the programmer specified by the argument. Programmers and their pin configurations are read from the config file (see the -C option). New pin configurations can be easily added or modified through the use of a config file to make avrdude work with different programmers as long as the programmer supports the Atmel AVR serial program method. You can use the 'default_programmer' keyword in your ${HOME}/.config/avrdude/avrdude.rc or ${HOME}/.avrduderc file to assign a default programmer to keep from having to specify this option on every invocation. A full list of all supported programmers is output to the terminal by using ? as programmer-id. If -c ? is specified with a specific part, see -p above, then only those programmers are output that expect to be able to handle this part, together with the programming interface(s) that can be used in that combination. In reality there can be deviations from this list, particularly if programming is directly via a bootloader.

Run developer options for programmers that are matched by wildcard. Whilst their main use is for developers some flags can be of utility for users, e.g., avrdude -c usbtiny/S shows AVRDUDE's understanding of usbtiny's properties; for more information run avrdude -c x/h.

Use the specified config file to load configuration data. This file contains all programmer and part definitions that avrdude knows about. See the config file, located at ${PREFIX}/etc/avrdude.conf, which contains a description of the format.

If config-file is written as +filename then this file is read after the system wide and user configuration files. This can be used to add entries to the configuration without patching your system wide configuration file. It can be used several times, the files are read in same order as given on the command line.

Do not load the personal configuration file that is usually located at ~/.config/avrdude/avrdude.rc, ~/.avrduderc or in the same directory as the avrdude executable

Disable the automatic removal of trailing-0xFF sequences in file input that is to be programmed to flash and in AVR reads from flash memory. Normally, trailing 0xFFs can be discarded, as flash programming requires the memory be erased to 0xFF beforehand. -A should be used when the programmer hardware, or bootloader software for that matter, does not carry out chip erase and instead handles the memory erase on a page level. Popular Arduino bootloaders exhibit this behaviour; for this reason -A is engaged by default when specifying -c arduino.

Disable auto-erase for flash. When the -U option for writing to any flash memory is specified, avrdude will perform a chip erase before starting any of the programming operations, since it generally is a mistake to program the flash without performing an erase first. This option disables that. Auto-erase is not used for ATxmega parts nor for the UPDI (AVR8X family) parts as these can use page erase before writing each page so no explicit chip erase is required. Note, however, that any flash page not affected by the current operation will retain its previous contents. Setting -D implies -A.

Causes a chip erase to be executed. This will reset the contents of the flash ROM and EEPROM to the value ‘0xff’, and clear all lock bits. Except for ATxmega and UPDI (AVR8X family) devices, all of which can use page erase, it is basically a prerequisite command before the flash ROM can be reprogrammed again. The only exception would be if the new contents would exclusively cause bits to be programmed from the value ‘1’ to ‘0’. This option carries out the chip erase at the beginning, before any of the -U, -T or -t options are processed. If a chip erase is required in at a certain position within the sequence of -U, -T or -t options it is recommended to use -T erase instead which is processed in the given command line order.

In absence of an explicit -e or -D option avrdude tries to augur from the command line whether or not the chip should be auto-erased at the beginning. If avrdude detects a -U command that writes to flash then auto-erase will be carried out before any other programming unless a -T erase commad has been detected beforehand and unless flash is read before writing to it. For the purpose of this analysis any terminal command is considered to possibly read flash.

Note that for reprogramming EEPROM cells, no explicit prior chip erase is required since the MCU provides an auto-erase cycle in that case before programming the cell.

Pass exitspec to the chosen programmer. The interpretation of the exitspec parameter depends on the programmer itself. See below for a list of programmers accepting exitspec parameter options or issue avrdude -E help ... to see the options of the chosen programmer.

Normally, avrdude tries to verify that the device signature read from the part is reasonable before continuing. Since it can happen from time to time that a device has a broken (erased or overwritten) device signature but is otherwise operating normally, this option is provided to override the check. Also, for programmers like the Atmel STK500 and STK600 which can adjust parameters local to the programming tool (independent of an actual connection to a target controller), this option can be used together with -t to continue in terminal mode. Moreover, the option allows to continue despite failed initialization of connection between a programmer and a target.

For bitbang-type programmers, delay for approximately delay microseconds between each bit state change. If the host system is very fast, or the target runs off a slow clock (like a 32 kHz crystal, or the 128 kHz internal RC oscillator), this can become necessary to satisfy the requirement that the ISP clock frequency must not be higher than 1/4 of the CPU clock frequency. This is implemented as a spin-loop delay to allow even for very short delays. On Unix-style operating systems, the spin loop is initially calibrated against a system timer, so the number of microseconds might be rather realistic, assuming a constant system load while avrdude is running. On Win32 operating systems, a preconfigured number of cycles per microsecond is assumed that might be off a bit for very fast or very slow machines.

Use logfile rather than stderr for diagnostics output. Note that initial diagnostic messages (during option parsing) are still written to stderr anyway.

No-write: disables writing data to the MCU whilst processing -U (useful for debugging avrdude ). The terminal mode continues to write to the device.

Perform an RC oscillator run-time calibration according to Atmel application note AVR053. This is only supported on the STK500v2, AVRISP mkII, and JTAG ICE mkII hardware. Note that the result will be stored in the EEPROM cell at address 0.

Use port to identify the connection through which the programmer is attached. This can be a parallel, serial, spi or linuxgpio connection. The programmer normally specifies the connection type; in absence of a -P specification, system-dependent default values default_parallel, default_serial, default_spi, or default_linuxgpio from the configuration file are used. If you need to use a different port, use this option to specify the alternate port name.

If avrdude has been configured with libserialport support, a serial port can be specified using a predefined serial adapter type in avrdude.conf or .avrduderc, e.g., ch340 or ft232r. If more than one serial adapter of the same type is connected, they can be distinguished by appending a serial number, e.g., ft232r:12345678. Note that the USB to serial chip has to have a serial number for this to work. Avrdude can check for leading and trailing serial number matches as well. In the above example, ft232r:1234 would also result in a match, and so would ft232r:...5678. If the USB to serial chip is not known to avrdude, it can be specified using the hexadecimal USB vendor ID, hexadecimal product ID and an optional serial number, following the serial number matching rules described above, e.g., usb:0x2341:0x0043 or usb:2341:0043:12345678. To see a list of currently plugged-in serial ports use -P ?s. In order to see a list of all possible serial adapters known to avrdude use -P ?sa.

On Win32 operating systems, the parallel ports are referred to as lpt1 through lpt3, referring to the addresses 0x378, 0x278, and 0x3BC, respectively. If the parallel port can be accessed through a different address, this address can be specified directly, using the common C language notation (i.e., hexadecimal values are prefixed by ‘0x’ ).

For the JTAG ICE mkII and JTAGICE3, if avrdude has been configured with libusb support, port can alternatively be specified as usb[:serialno]. This will cause avrdude to search the programmer on USB. If serialno is also specified, it will be matched against the serial number read from any JTAG ICE mkII found on USB. The match is done after stripping any existing colons from the given serial number, and right-to-left, so only the least significant bytes from the serial number need to be given.

As the AVRISP mkII device can only be talked to over USB, the very same method of specifying the port is required there.

For the USB programmer "AVR-Doper" running in HID mode, the port must be specified as avrdoper. Libhidapi support is required on Unix and Mac OS but not on Windows. For more information about AVR-Doper see https://www.obdev.at/products/vusb/avrdoper.html.

For the USBtinyISP, which is a simplistic device not implementing serial numbers, multiple devices can be distinguished by their location in the USB hierarchy. See the respective Troubleshooting entry in the detailed documentation for examples.

For the XBee programmer the target MCU is to be programmed wirelessly over a ZigBee mesh using the XBeeBoot bootloader. The ZigBee 64-bit address for the target MCU's own XBee device must be supplied as a 16-character hexadecimal value as a port prefix, followed by the ‘@’ character, and the serial device to connect to a second directly contactable XBee device associated with the same mesh (with a default baud rate of 9600). This may look similar to: 0013a20000000001@/dev/tty.serial.

For diagnostic purposes, if the target MCU with an XBeeBoot bootloader is connected directly to the serial port, the 64-bit address field can be omitted. In this mode the default baud rate will be 19200.

For programmers that attach to a serial port using some kind of higher level protocol (as opposed to bit-bang style programmers), port can be specified as net:host:port. In this case, instead of trying to open a local device, a TCP network connection to (TCP) port on host is established. Square brackets may be placed around host to improve readability, for numeric IPv6 addresses (e.g. net:[2001:db8::42]:1337). The remote endpoint is assumed to be a terminal or console server that connects the network stream to a local serial port where the actual programmer has been attached to. The port is assumed to be properly configured, for example using a transparent 8-bit data connection without parity at 115200 Baud for a STK500.

Note: The ability to handle IPv6 hostnames and addresses is limited to Posix systems (by now).

Disable (or quell) output of the progress bar while reading or writing to the device. Specify it more often for even quieter operations.

These options used to control the obsolete "safemode" feature which is no longer present. They are silently ignored for backwards compatibility.

Run terminal line cmd when it is its turn in relation to other -t interactive terminals -T terminal commands and -U memory operations. Except for the simplest of terminal commands the argument cmd will most likely need to be set in quotes, see your OS shell manual for details. See below for a detailed description of all terminal commands.

Tells avrdude to run an interactive terminal when it is its turn in relation to other -t interactive terminals, -T terminal commands and -U memory operations.

Perform a memory operation as indicated when it is its turn in relation to other -t interactive terminals, -T terminal commands and -U memory operations. The memory field specifies the memory to operate on. From version 8.0 the memory field can also be a comma-separated list of memories, eg, flash,eeprom; also, Intel Hex or Motorola S-Record files generated by AVRDUDE can store multiple memories. The special memory ALL expands to all memories that a part has while all expands to all memories with exception of sub-memories. etc is the same as all; this can be used to change the order in which memories are written to or read from file, eg, signature,etc is a list of all memories such that the signature memory comes first. It is possible to remove a memory from the list so far by preceding a minus or backslash, eg, all,-calibration. The available memory types are device-dependent, the actual configuration can be viewed with the part command in terminal mode.

Typically, a device's memory configuration at least contains the memories flash, eeprom, signature and lock, which is sometimes known as lockbits. The signature memory contains the three device signature bytes, which should be, but not always are, unique for the part. The lock memory of one or four bytes typically details whether or not external reading/writing of the flash memory, or parts of it, is allowed. After restricting access via the lock memory, often the only way to unlock memory is via a chip erase. Parts will also typically have fuse bytes, which are read/write memories for configuration of the device and calibration memories that typically contain read-only factory calibration values.

The flash memory, being physically implemented as NOR-memory, is special in the sense that it is normally only possible to program bits to change from 1 to 0. Before reprogramming takes place normally flash memory has to be erased. Older parts would only offer a chip erase to do so, which also erases EEPROM unless a fuse configuration preserves its contents. If AVRDUDE detects a -U option that writes to a flash memory it will automatically trigger a chip erase for these older parts. ATxmegas or UPDI parts (AVR8X family) offer a page erase, and AVRDUDE takes advantage of that by erasing pages before programming them unless -e (chip erase) or -D (do not erase before writing) was requested. It should be noted that in absence of the -e chip erase option any ATxmega or UPDI flash pages not affected by the programming will retain their previous content.

For a list of all known memories, please refer to the full documentation, eg, https://github.com/avrdudes/avrdude/blob/main/avrdude.pdf

The op field specifies what operation to perform:

r

read device memory and write to the specified file

w

read data from the specified file and write to the device memories in the list; read-only memories in a memory list are skipped, as are fuses and lock bits when the programmer is a bootloader; writing to single read-only memories fails only if the contents differs between the file and memory

v

read data from both the device and the specified file and perform a verify

The filename field indicates the name of the file to read or write. The format field is optional and contains the format of the file to read or write. Format can be one of:

i

Intel Hex

I

Intel Hex with comments on reading from, and tolerance of checksum errors, writing to the AVR

s

Motorola S-Record

r

raw binary; little-endian byte order, in the case of the flash data

e

ELF (Executable and Linkable Format, for input only)

m

immediate mode; actual byte values are specified on the command line, separated by commas or spaces in place of the filename field of the -U option. This is useful for programming fuse bytes without having to create a single-byte file or enter terminal mode.

a

auto detect; valid for input only, and only if the input is not provided at stdin.

d

decimal; this and the following formats generate one line of output for the respective memory section, forming a comma-separated list of the values. This can be particularly useful for subsequent processing, like for fuse bit settings.

h

hexadecimal; each value will get the string 0x prepended.

o

octal; each value will get a 0 prepended unless it is less than 8 in which case it gets no prefix.

b

binary; each value will get the string 0b prepended.

When used as input, the m, d, h, o and b formats will use the same code for reading lists of numbers separated by white space and/or commas. The read routine handles decimal, hexadecimal, octal or binary numbers on a number-by-number basis, and the list of numbers can therefore be of mixed type. In fact the syntax, is the same as for data used by the terminal write command, i.e., the file's input data can also be 2-byte short integers, 4-byte long integers or 8-byte long long integers, 4-byte floating point numbers, 8-byte double precision numbers, C-type strings with a terminating nul or C-like characters such as ''. Numbers are written as little endian to memory. When using 0x hexadecimal or 0b binary input leading zeros are used to determine the size of the integer, e.g., 0x002a will occupy two bytes and write a 0x2a to memory followed by 0x00, and 0x01234 will occupy 4 bytes. See the description of the terminal write command for more details.

In absence of an explicit file format, the default is to use auto detection for input files, raw binary format for output files from a single memory read and Intel Hex with comments when an output file is generated from a list of memories. Note that while avrdude will generate a single output file from a memory list for all formats with the exception of elf (:e) it only recognises Intel hex (:I or :i), Motorola S-Record (:s) or elf files (:e, generated by the compiler) as valid multi-memory files when reading a file for verifying or writing memories. Note also that if a filename contains a colon as penultimate character the format field is no longer optional since the last character would otherwise be misinterpreted as format.

When reading any kind of flash memory area (including the various sub-areas in Xmega devices), the resulting output file will be truncated to not contain trailing 0xFF bytes which indicate unprogrammed (erased) memory. Thus, if the entire memory is unprogrammed, this will result in an output file that has no contents at all. This behaviour can be overridden with the -A option.

As an abbreviation, the form -U filename is equivalent to specifying -U flash:w:filename:a. This will only work if filename does not have a pair of colons in it that sandwich a single character as otherwise the first part might be interpreted as memory, and the single character as memory operation.

Enable verbose output. More -v options increase verbosity level.

Disable automatic verify check when writing data to the AVR with -U.

Pass extended_param to the chosen programmer implementation as an extended parameter. The interpretation of the extended parameter depends on the programmer itself. See below for a list of programmers accepting extended parameters or issue avrdude -x help ... to see the extended options of the chosen programmer.

Read from the specified memory interval (see above), and display in the usual hexadecimal and ASCII form.

Read from memory addr as many bytes as the most recent dump memory addr len command with this very memory had specified (default 256 bytes), and display them.

Continue dumping the contents from the same memory where the previous dump memory command left off.

Continue dumping from the memory and location where the most recent dump command left off; if no previous dump command has addressed a memory an error message will be shown.

Read all bytes from the specified memory starting at address addr, and display them (deprecated: use dump memory addr -1).

Read all bytes from the specified memory, and display them (deprecated: use dump memory 0 -1).

Can be used as an alias for dump.

Like dump, the disasm command displays a part of the specified memory, albeit by interpreting the memory contents as AVR opcodes and showing it as assembler source code. Unlike dump, the disasm command has options; these control how disasm displays its result (see below). Other than that, the syntax of specifying the memory and its to be processed interval is virtually the same as that of dump: the default disasm length is 32 bytes, though, and sometimes the length can be slightly shorter or longer than requested, so that the memory section for disasm aligns with opcodes. Disasm options, once set, stay in force until switched off, typically by changing the case of the option. This way, a simple disasm without further options can be used to step through memory keeping the appearance. Disasm knows the following options:

The tagfile is an ASCII file where each line describes a symbol for code label addresses (L), variable addresses in flash (P) and variables addresses in memory or I/O space (M). Hashmarks start a tagfile comment that extends to the end of the line and is ignored by disasm. Here is a defining example of how a tagfile looks like

---------------------------------------------------------------
0x7f54 L        putch     Outputs a char # L are code labels
0x7ffe P W 1    version16 A word integer # P are PGM data
0x7f80 P A 4    headings  Column headers # Auto-aligned strings
0x0100 M B 2048 sram      2 kB SRAM      # Memory address
---------------------------------------------------------------
    

Code labels L can be, eg, function names in program space or goto labels. They use up to four columns separated by white space: the address, the letter L, the symbolic name of the label and an optional comment column for the symbol, which is copied by disasm into the disassembly comment column, should this label be referenced or used by the code. Variable symbols have a P or M in the second column; they can be bytes or words as determined by the letter B or W in the third column and either single variables or arrays as specified by the multiplicity count in the forth column. P symbols, but not M symbols, can also be the base location of nul-terminated strings as encoded by A or S in the third column. Out of necessity, the space occupied by A/S strings varies. The difference between A and S symbols is that the array of A strings might have an additional nul character to auto-align the space occupied by them to an even address. The fifth column is the symbolic name for the P or M address that can be used by disasm to output relevant addresses symbolically. P areas described in the tagfile also tell disasm that the corresponding area is not code and should not be disassembled as such; instead the directives are used for disassembly of that area. As with L labels, P and M variables may have an optional final comment column pertaining to the symbol that may be output in the disassembly column as and when the corresponding variables are used.

Tagfiles are useful for disassembly to make the output of disasm more readable. They can be built manually and incrementally as one's understanding of the code grows. Alternatively, the bash shell script elf2tag can automatically generate a tag file from the .elf file that produced the flash contents:

$ elf2tag file.elf >file.tag

elf2tag uses the avr-objdump -d disassembly to create L labels and avr-nm to generate M symbols.

Manually program the respective memory cells, starting at address addr, using the data items provided. The terminal implements reading from and writing to flash, EEPROM, bootrow and usersig type memories normally through a cache and paged access functions. All other memories are directly written to without use of a cache. Some older parts without paged access, depending on the programmer, might also have flash and EEPROM directly accessed without cache.

data can be binary, octal, decimal or hexadecimal integers, floating point numbers or C-style strings and characters. If nothing matches, data will be interpreted as the name of a file containing data, which will be read and inserted at this point. In order to force the interpretation of a data item as file, e.g., when the file name would be understood as a number otherwise, the file name can be given a :f format specifier. In absence of a format suffix, the terminal will try to auto-detect the file format.

For integers, an optional case-insensitive suffix specifies the data size: HH 8 bit, H/S 16 bit, L 32 bit, LL 64 bit. Suffix D indicates a 64-bit double, F a 32-bit float, whilst a floating point number without suffix defaults to 32-bit float. Hexadecimal floating point notation is supported. An ambiguous trailing suffix, e.g., 0x1.8D, is read as no-suffix float where D is part of the mantissa; use a zero exponent 0x1.8p0D to clarify.

An optional U suffix makes integers unsigned. Ordinary 0x hexadecimal and 0b binary integers are always treated as unsigned. +0x, -0x, +0b and -0b numbers with an explicit sign are treated as signed unless they have a U suffix. Unsigned integers cannot be larger than 2^64-1. If n is an unsigned integer then -n is also a valid unsigned integer as in C. Signed integers must fall into the [-2^63, 2^63-1] range or a correspondingly smaller range when a suffix specifies a smaller type.

Ordinary 0x hexadecimal and 0b binary integers with n digits (counting leading zeros) use the smallest size of one, two, four and eight bytes that can accommodate any n-digit hexadecimal/binary integer. If an integer suffix specifies a size explicitly the corresponding number of least significant bytes are written, and a warning shown if the number does not fit into the desired representation. Otherwise, unsigned integers occupy the smallest of one, two, four or eight bytes needed. Signed numbers are allowed to fit into the smallest signed or smallest unsigned representation: For example, 255 is stored as one byte as 255U would fit in one byte, though as a signed number it would not fit into a one-byte interval [-128, 127]. The number -1 is stored in one byte whilst -1U needs eight bytes as it is the same as 0xFFFFffffFFFFffffU.

One trailing comma at the end of data items is ignored to facilitate copy & paste of lists.

The start address addr may be omitted if the size of the memory being written to is one byte.

The ellipsis ... form writes the data to the entire memory intervall addressed by addr len and, if necessary, pads the remaining space by repeating the last data item. The fill write command does not write beyond the specified memory area even if more data than needed were given.

Save one or more memory segments to a file in a format specified by the :format letter. The default is :r for raw binary. Each memory segment is described by an address and length pair. In absence of any memory segments the entire memory is saved to the file. Only Motorola S-Record (:s) and Intel Hex (:i or :I) formats store address information with the saved data. Avrdude cannot currently save ELF file formats. All the other file formats lose the address information and concatenate the chosen memory segments into the output file. If the file name is - then avrdude writes to stdout.

Backup one or more memories to the specified file using the selected format. The default format for a single-memory backup is :r (raw binary); for multi-memory backups it is :I (Intel Hex with comments). Memlist can be a comma separated list of memories just as in the -U command line argument. backup flushes the cache before reading memories.

Restore one or more memories from the specified file. It is the user's responsibility to erase memories as needed beforehand: some paged memories look like NOR-memory when using certain programmers, meaning programming cannot set bits to 1 (eg, flash under most programmers). These memories need to be erased beforehand using the erase command (see below). The format only needs to be specified if it cannot be automatically detected, eg, when the file is - for standard input. Memlist can be a comma separated list of memories just as in the -U command line argument. restore flushes the cache before writing memories and resets the cache after writing memories. Note that restoring read-only memories verifies file contents with the corresponding microprocessor's memories.

Compare one or more memories with the specified file. Memlist can be a comma separated list of memories just as in the -U command line argument. verify flushes the cache before verifying memories.

Perform a chip erase and discard all pending writes to flash, EEPROM and bootrow. Note that EEPROM will be preserved if the EESAVE fuse bit is active, ie, had a corresponding value at the last reset prior to the operation.

Erase the entire specified memory.

Erase a section of the specified memory.

Synchronise with the device all pending writes to flash, EEPROM, bootrow and usersig. With some programmer and part combinations, flash (and sometimes EEPROM, too) looks like a NOR memory, i.e., a write can only clear bits, never set them. For NOR memories a page erase or, if not available, a chip erase needs to be issued before writing arbitrary data. Usersig is unaffected by a chip erase. When a memory looks like a NOR memory, either page erase is deployed (e.g., with parts that have PDI/UPDI interfaces), or if that is not available, both EEPROM and flash caches are fully read in, a chip erase command is issued and both EEPROM and flash are written back to the device. Hence, it can take minutes to ensure that a single previously cleared bit is set and, therefore, this routine should be called sparingly.

Normally, caches are only ever actually written to the device when using the flush command, at the end of the terminal session after typing quit, or after EOF on input is encountered. The abort command resets the cache discarding all previous writes to the flash, EEPROM, bootrow and usersig cache.

Show all configuration properties of the part; these are usually bitfields in fuses or lock bits bytes that can take on values, which typically have a mnemonic name. Each part has their own set of configurable items. The option -f groups the configuration properties by the fuses and lock bits byte they are housed in, and shows the current value of these memories as well. Config -a outputs an initialisation script with all properties and all possible respective assignments. The currently assigned mnemonic values are the ones that are not commented out. The option -v increases the verbosity of the output of the config command.

Show the current value of the named configuration property. Wildcards or initial strings are permitted (but not both), in which case the current values of all matching properties are displayed.

Show all possible values of the named configuration property (notice the trailing =). The one that is currently set is the only one not commented out. As before, wildcards or initial strings are permitted.

Modify the named configuration property to the given value. The corresponding fuse or lock bits will be changed immediately but the change will normally only take effect the next time the part is reset, at which point the fuses and lock bits are utilised. Value can either be a valid integer or one of the symbolic mnemonics, if known. Wildcards or initial strings are permitted for either the property or the assigned mnemonic value, but an assignment only happens if both the property and the name can be uniquely resolved.

It is quite possible, as is with direct writing to the underlying fuses and lock bits, to brick a part, i.e., make it unresponsive to further programming with the chosen programmer: here be dragons.

Resets the connected part to factory state as far as possible (bootloaders, for example, cannot write fuses and may not have a means to erase EEPROM). This command may change the clock frequency F_CPU of the part after the next MCU reset when the changed fuse values come into effect. As such, this may require that future avrdude calls use a different bit clock rate up to F_CPU/4 for the programmer next time. Note that the command factory can be abbreviated but the required argument reset needs to be spelled out in full.

regfile with no further argument displays the register file of a part, i.e., all register names and their contents in io memory, if possible: note that external programming cannot read the registers of classic parts (ISP or TPI interfaces).

Option -a displays the register I/O addresses in addition; -m displays the register memory addresses used for lds/sts opcodes instead of the I/O addresses. Option -s also shows the size of the register in bytes whilst -v shows a slightly expanded register explanation alongside each register.

regfile together with a register name reg shows all those registers that are matched by reg. Wildcards or partial strings are permitted but not both. Register names have the form module.name or module.instance.name. If the provided reg is a full, existing register name, e.g., porta.out then that is the only register that is displayed even though that might be a partial name of another register, eg, porta.outdir. If the provided is the same as instance.name or name then partial matching is no longer utilised and all module registers with that exact instance.name or name are shown. Partial matching can be forced through use of wildcards, e.g., porta.out*

This sets a single register addressed by reg to the given value. Only external programming of modern parts (those with UPDI interface) can read from and write to register io memory, but as that memory is volatile, the contents will be lost after reset.

Include contents of the named file as if it was typed. This is useful for batch scripts, e.g., recurring initialisation code for fuses. The include option -e prints the lines of the file as comments before processing them; on a non-zero verbosity level the line numbers are printed, too.

Display the device signature bytes.

Display the current part information, including supported programming modes, memory and variants tables. Use -m to only print the memory table, and -v to only print the variants table.

Change (when level is provided), or display the verbosity level. The initial verbosity level is controlled by the number of -v options given on the commandline.

Change (when level is provided), or display the quell level. 1 is used to suppress progress reports. 2 or higher yields in progressively quieter operations. The initial quell level is controlled by the number of -q options given on the commandline.

Give a short on-line summary of the available commands.

Leave terminal mode and thus avrdude.

Can be used as an alias for quit.

Run the shell <line> in a subshell, e.g., !ls *.hex. Subshell commands take the rest of the line as their command. For security reasons, they must explictly be enabled by putting allow_subshells = yes; into your ${HOME}/.config/avrdude/avrdude.rc or ${HOME}/.avrduderc file.

Place comments onto the terminal line (useful for scripts).

Erase one page of the memory specified.

Send raw instruction codes to the AVR device. If you need access to a feature of an AVR part that is not directly supported by avrdude, this command allows you to use it, even though avrdude does not implement the command. When using direct SPI mode, up to 3 bytes can be omitted.

Enter direct SPI mode. The pgmled pin acts as chip select. Supported on parallel bitbang programmers, and partially by USBtiny.

Return to programming mode (from direct SPI mode).

Set the target's supply voltage to voltage Volts. Supported on the STK500 and STK600 programmer.

Set the adjustable voltage source to voltage Volts. This voltage is normally used to drive the target's Aref input on the STK500. On the Atmel STK600, two reference voltages are available, which can be selected by the optional channel argument (either 0 or 1). Supported on the STK500 and STK600 programmer.

Set the programming oscillator to freq Hz. An optional trailing letter M multiplies by 1E6, a trailing letter k by 1E3. Supported on the STK500 and STK600 programmer.

Turn the programming oscillator off. Supported on the STK500 and STK600 programmer.

Set the SCK clock period to period microseconds. Note that some official Microchip programmers store the bitclock setting and will continue to use it until a diferent value is provided. See -B bitclock for more information.

Display programmer specific parameters.

These two programmers emulate programming and accept the following parameters:

When using the JTAG ICE mkII, JTAGICE3, Atmel-ICE, PICkit 4, MPLAB SNAP, Power Debugger or AVR Dragon in JTAG mode, the following extended parameter is accepted:

When using the Wiring programmer type, the following optional extended parameters are accepted:

Connection to the PICkit2 programmer:

(AVR)    (PICkit2)
RST  -   VPP/MCLR (1)
VDD  -   VDD Target (2) -- possibly optional if AVR self powered
GND  -   GND (3)
SDI  -   PGD (4)
SCLK -   PDC (5)
SDO  -   AUX (6)