[avrdude-dev] [patch #4330] Adds experimental FTDI bit bang mode interface

[Thomas Fischl]

Follow-up Comment #1, patch #4330 (project avrdude):

I find this ftbb patch very useful! On target systems which works with a FTDI
usb converter chip, the bitbang lines can be easily used for the isp signals.
No additional isp connector is needed and the target controller can be
programmed over USB without extra wiring.

I've attached an improved version of this ftbb patch. Jonathan ported it to
libftdi, so it can be used on Linux systems. Because programming speed was
not so fast, I modified his patch a bit. I changed only parts of ftbb.c, the
rest is Jonathan's work (thanks!).

There are two main modifications:
1. On isp commands the sequence of outgoing singals is buffered. Readback is
only done if necessary. This method prevent switching between sending and
receiving from the FTDI chip on each bit.
2. Using own programming commands (paged_write) make writing faster. The
output sequence can be better buffered on paged writes.

Here is a small list of writing and reading durations on my system (only
tested under MacOS) with a 2240 byte testfile:
Without changes:
- Reading and writing both about 230s
With buffered mode but without paged writing:
- Reading and writing both about 43s
With buffered mode and with paged writing:
- Writing: 3.36s
- Reading: 43s

The code includes calls for the FTDI DLL, but that wasn't tested yet. Perhaps
there are some modifications needed to compile it under windows with the FTDI
DLL.

The patch was created for current cvs version (2006-12-30). To compile with
ftdi-support type:
./configure --enable-ftdi-support

-Thomas

(file #11627, file #11628, file #11629, file #11630)
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Additional Item Attachment:

File name: patch-avrdude-ftbb-20061230.diff Size:3 KB
File name: ftbb.h                         Size:1 KB
File name: ftbb.c                         Size:13 KB
File name: ftbb_ftdi.m4                   Size:1 KB


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