All Atmel-provided CMSIS-DAP devices use 512 byte packet size 45/2045/3
authorJörg Wunsch <>
Fri, 14 Mar 2014 10:00:54 +0000 (11:00 +0100)
committerSpencer Oliver <>
Mon, 17 Mar 2014 12:49:07 +0000 (12:49 +0000)
All Atmel-provided CMSIS-DAP devices use 512 byte packet size

The existing CMSIS-DAP driver matches the USB VID/PID against 0x3eb
(Atmel VID) and 0x2111 (Atmel EDBG embedded CMSIS-DAP debugger), and
then bumps the packet size from its default of 64 to 512.  However, it
turned out that *all* Atmel-provided CMSIS-DAP devices (EDBG with PID
0x2111; JTAGICE3 with firmware version 3.x, PID 0x2140; new Atmel-ICE
[successor of JTAGICE3], PID 0x2141) require a 512-byte packet size.
Obviously, all run the same USB implementation inside their custom
microcontroller.  Thus, it seems best to simply assume that *all*
Atmel CMSIS-DAP devices use this packet size, and don't check the PID
at all.

This has also been filed as Trac bug #68:

Change-Id: I942af93060fdf265fca3961841638caa6182f877
Signed-off-by: Jörg Wunsch <>
Tested-by: jenkins
Reviewed-by: Spencer Oliver <>
Reviewed-by: Andrey Yurovsky <>

Linking to existing account procedure

If you already have an account and want to add another login method you MUST first sign in with your existing account and then change URL to read to get to this page again but this time it'll work for linking. Thank you.

SSH host keys fingerprints

1024 SHA256:YKx8b7u5ZWdcbp7/4AeXNaqElP49m6QrwfXaqQGJAOk (DSA)
384 SHA256:jHIbSQa4REvwCFG4cq5LBlBLxmxSqelQPem/EXIrxjk (ECDSA)
521 SHA256:UAOPYkU9Fjtcao0Ul/Rrlnj/OsQvt+pgdYSZ4jOYdgs (ECDSA)
256 SHA256:A13M5QlnozFOvTllybRZH6vm7iSt0XLxbA48yfc2yfY (ECDSA)
256 SHA256:spYMBqEYoAOtK7yZBrcwE8ZpYt6b68Cfh9yEVetvbXg (ED25519)
+--[ED25519 256]--+
|=..              |
|+o..   .         |
|*.o   . .        |
|+B . . .         |
|Bo. = o S        |
|Oo.+ + =         |
|oB=.* = . o      |
| =+=.+   + E     |
|. .=o   . o      |
2048 SHA256:0Onrb7/PHjpo6iVZ7xQX2riKN83FJ3KGU0TvI0TaFG4 (RSA)