[avrdude-dev] [bug #46587] patch: transparent SPI (relay) mode

[anonymous]

URL:
  <http://savannah.nongnu.org/bugs/?46587>

                 Summary: patch: transparent SPI (relay) mode
                 Project: AVR Downloader/UploaDEr
            Submitted by: None
            Submitted on: Wed 02 Dec 2015 07:30:22 AM UTC
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: Tibor 'Igor2' Palinkas
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any

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Details:

(This is not a bug report but a patch for a new feature. This was the
only tracker I could add it to without registration.)

In my next open source hardware project I program an attiny to be an SPI
slave. I figured the easiest way to test the firmware would be to use my
parallel port avr programmer device to emulate an SPI bus master. For this
I need avrdude to be able to:

- avoid resetting the target device
- omit any SPI commands related to AVR programming during initialization
- initiate arbitrary long SPI transactions

The patch attached implements this in the following steps.

1. a new device flag AVRPART_NO_RESET can disable the reset signal
normally generated for no-tpi devices

2. a new device configuration called "spi" or "transparent_spi" defines
a device that omits the reset and all SPI communication during initialization

3. a new command line switch -S puts avrdude in transparent SPI mode

4. in transparent SPI mode binary data is relayed between stdio and SPI until
EOF on stdin.

I've tested it with a parallel port programmer and a scope, with
MISO-MOSI looped back with a wire, left unconnected or an attiny2313
connected. Both the transparent SPI mode and programming the attiny worked.
I have no idea if it works with non-bitbang programmers.

Command line for the transparent SPI mode: avrdude -c <whatever> -p spi -S




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File Attachments:


-------------------------------------------------------
Date: Wed 02 Dec 2015 07:30:22 AM UTC  Name: SPI.patch  Size: 9kB   By: None
svn diff in trunk/avrdude
<http://savannah.nongnu.org/bugs/download.php?file_id=35611>

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