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[avrdude-dev] [bug #47890] ft232r serial dongle connected to ponyser int
From: |
Christian Mueller |
Subject: |
[avrdude-dev] [bug #47890] ft232r serial dongle connected to ponyser interface |
Date: |
Tue, 10 May 2016 18:07:35 +0000 (UTC) |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Iceweasel/38.7.1 |
URL:
<http://savannah.nongnu.org/bugs/?47890>
Summary: ft232r serial dongle connected to ponyser interface
Project: AVR Downloader/UploaDEr
Submitted by: cm1
Submitted on: Tue May 10 18:07:34 2016
Category: None
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Privacy: Public
Assigned to: None
Originator Name: Christian Mueller
Originator Email:
Open/Closed: Open
Discussion Lock: Any
_______________________________________________________
Details:
I tried to get a regular USB/RS232 adapter with an FT232R chip working on a
board/programmer using the "ponyser" interface using type "ftdi_syncbb".
However, the [oscillo]scope showed that both clk and mosi, which are inverted
in my configuration, jumped back to high levels directly after each command.
It turned out that ft245r_cmd(), line 518, finishes by simply sending a
0-byte, ignoring pins that might be inverted:
for (i=0; i<4; i++) {
buf_pos += set_data(pgm, buf+buf_pos, cmd[i]);
}
buf[buf_pos] = 0;
buf_pos++;
The following should work better:
for (i=0; i<4; i++) {
buf_pos += set_data(pgm, buf+buf_pos, cmd[i]);
}
ft245r_out = SET_BITS_0(ft245r_out,pgm,PIN_AVR_SCK,0);
ft245r_out = SET_BITS_0(ft245r_out,pgm,PIN_AVR_MOSI,0);
buf[buf_pos] = ft245r_out;
buf_pos++;
NOTE: The RS232 dongle still didn't work in the end but the scope showed
correct signal levels. It also showed, however, that my dongle apparently
doesn't provide enough current to switch the signals fast enough so that the
peak-to-peak voltage at the default baud rate for CLK was only around 2.5V...
I gave up on this for the time being - I still do have a regular RS232 port in
my computer - but I thought it would be good to keep track of the issue, hence
this bug report.
For what it's worth at this point, here's the configuration for this
combination (haven't checked whether MISO is inverted or not because I've
never seen anything on that pin):
# ponyser serial design with regular FT232R USB/serial adapter
programmer
id = "ponyser-ft232r";
desc = "ponyser serial design, using FT232R Synchronous BitBang";
type = "ftdi_syncbb";
connection_type = usb;
miso = ~3; # CTS
sck = ~2; # RTS
mosi = ~4; # DTR
reset = ~0; # TXD
;
_______________________________________________________
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