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Re: [avrdude-dev] AVR910 with firmware 3.2 - two problems


From: Charles Steinkuehler
Subject: Re: [avrdude-dev] AVR910 with firmware 3.2 - two problems
Date: Tue, 30 Mar 2004 16:11:01 -0600
User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.6) Gecko/20040113

Thomas Fischl wrote:

I've built an avr910 programmer based on AT90S2313 with firmware version
3.2. I used the description from http://www.mikrocontroller-projekte.de/.
With AVRDUDE there are two problems:
1. the single-byte 'y' command to clear the LED in avr910_write_setup. This
was discussed earlier on the list, but the current CVS version still has this
problem.
2. write memory command fails after the first page is written to the device.
the programmer needs the address before the pagedata are written: setaddress
('A'), load page data ('c'/'C'), setaddress ('A'), write page ('m'). It
seems that AvrProg and UISP also use this sequence for programming the flash.

My solutions:
1. write an ESC command instead an LED-command and check the response which
has to be a '?' (because ESC is an unknown command)

Um...ESC is *NOT* an unknown command. It is a special synchronizing character the host can send to the programmer to re-synchronize. The programmer returns *NOTHING* when it sees an escape sequence on it's input. This allows the host to send several escape characters to flush any pending programmer state (ie: waiting for byte N of a multi-byte command).

The proper fix for the 'y' command is to send 2 bytes: 'y' followed by 'ESC'. This will make the programmers that support a 2 byte 'y' command happy, and won't break the communications protocol by sending two response bytes on (broken) programmers with a single byte 'y' command.

...of course you can use whatever works for your system, but if your programmer returns a '?' when you send it an 'ESC', I don't know how it would work with anything, especially the Ateml programming SW (which I like to use as a test for 910-type programming SW).

--
Charles Steinkuehler
address@hidden




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