Hi,
I am using a custom USB to JTAG adapter, made by my university, to program a SAM7S256. This adapter uses an FT2232D chip and the GPIO used is GPIOL0 for nTRST and GPIOL1 for nRST. These pins are connected directly to a header on the adapter, and so when the adapter is connected to an MCU the signals go straight to the pins on the microcontroller.
Currently in my OpenOCD configuration script I use “ft2232_layout usbjtag”, which is the “USB-JTAG-1” layout from the OpenOCD diploma thesis. I chose this because it is so far the only layout I have found a schematic for (it is included in the diploma thesis). In the schematic for this adapter the FT2232’s GPIOL0 line is used for nTRST, its GPIOL1 line is used for RTCK, and its GPIOL2 Line is used for RST.
The only thing from “ft2232_layout usbjtag” which matches my custom USB to JTAG adapter is TRST. I don’t really care about RTCK, or even TRST (I don’t think it’s needed is it?). All I really want is to be able to use the reset signal.
I can load programs and debug the MCU successfully, but I can’t use the “reset” command from OpenOCD because OpenOCD is sending the reset signal to the wrong output pin of the FT2232D. I can only use “soft_reset_halt” at the moment.
My question is, can I manually change the layout somehow? Through the documentation [here I’ve found out about something called ftdi_layout_signal, but I don’t understand how to use it correctly.
Alternatively, does anybody know an ft2232_layout that will work for my adapter? I can’t seem to find anything that documents what the actual configurations of the adapter choices for “ft2232_layout” are.