view eeproms/jtag-unbuf @ 43:dbaf239436cf

doc/DUART28-EEPROM-config: update for fc-duart28-conf
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 11 Sep 2023 01:06:03 +0000
parents 434806360d91
children d46ea7a3fa0c
line wrap: on
line source

# This EEPROM configuration is meant to be programmed into COTS FT2232D
# breakout boards used as unbuffered JTAG adapters.  The custom USB VID:PID
# belongs to Falconia Partners LLC; we hereby allow the community to program
# this PID into generic FT2232D boards (not made by Falconia) as long as
# it is used for the present purpose with this full EEPROM configuration.
#
# The purpose of having a custom USB ID is to prevent the Linux kernel
# ftdi_sio driver from treating this FT2232D instance as a dual UART and
# creating a ttyUSB device for Channel A.  If you wish to use Channel B
# as a UART (which is still available for that purpose), you will need to use
# a Linux kernel version with commit 6cf87e5edd9944e1d3b6efd966ea401effc304ee
# included, or apply that commit locally if your kernel version does not
# include it.

vid 0x0403	# FTDI
pid 0x7151	# Allocated by FTDI to Falconia Partners LLC
manuf FTDI
product Unbuffered JTAG adapter

# We program Channel A to come up in the 245 FIFO mode prior to being
# switched into MPSSE mode by OpenOCD, as opposed to the default 232 UART mode.
# If the FT2232D chip's ADBUS pins are connected directly to the JTAG target
# without a buffer (what we mean by an unbuffered JTAG adapter), the default
# 232 UART mode is NOT safe, as it will produce a fight on the ADBUS2 line
# between the UART RTS output and the target's TDO output.  245 FIFO mode is
# expected to be safer, as all 8 ADBUS lines will be inputs for as long as
# the ACBUS2 line is left unconnected and not driven by anything.

byte00	0x01	# Channel A: FIFO mode, D2XX driver
byte01	0x08	# Channel B: UART mode, VCP driver