Tigard

An FTDI FT2232H-based multi-protocol tool for hardware hacking.

Objectives

There are plenty of -232H series breakout boards, but they are generally designed to be an easy way to adapt it to a specific use, and not designed for regularly plugging in to all different target systems.

The two exceptions are the Exodus Intelligence Hardware Interface Board which is not open hardware or commercially available, and TIMEP which is the origin and heritage of this project.

Software Features
Hardware Features
Usage
Debugging
Pinouts
Stripes and Tails
Dens (cases)
Serial Numbers
Getting Tigard

Software Features

In general, Tigard was designed to work as-is with several tools and libraries that already support the x232H family of chips. This includes:

USB-Serial drivers for UART access
OpenOCD and URJTAG for JTAG
Flashrom, libmpsse, pyftdi and other tools for SPI interfaces
libmpsse and pyftdi for I2C interfaces
iceprog for ice40 FPGAs
avrdude for AVR microcontrollers

Also, users have used Tigard with BMDA, Mitou jtag, VSCode, and SPI via FTDI

Hardware Features

Highlights:

Dual-port, with one dedicated to UART and the second shared with other interfaces
High-performance directional level shifters for 1.8 to 5.5v operation
Switch to choose between on-board 1.8, 3.3, and 5.0v supplies and vTarget
Switch to choose between SPI/JTAG and I2C/SWD modes
Logic analyser port to observe device-level signals (v1.0 and later)
Indicator lights to aid debugging

Usage

Hardware Hookup

Starting with the board completely disconnected:

Connect board to target system with clips or jumper wires
Select the correct mode either SPI/JTAG or SWD/I2C
Ensure that the voltage switch is in VTGT mode
Plug in the USB cable. The PWR and EN LEDs will illuminate
Power on your target.
If you connected VTGT to your target, the VTGT LED will illuminate. If not, you can now select your voltage with the voltage switch

Switches

There are two switches on Tigard to set the mode of operation. One controls voltage, one controls how several of the IO pins are wired. Both need to be set properly for a specific use mode. Details are in each of the interface sections further below, but here is a summary of the modes and their uses:

Voltage Switch

This switch chooses the reference voltage for the level shifters and the target system:

1V8, 3V3, and 5V all apply a voltage to the VTGT pin.
VTGT disconnects the VTGT pin from supplies, and depends on the wire connected to the target to set the level shifter voltage.

This results in 3 distinct use cases:

Target-Powered: Set the switch to VTGT and connect the VTGT wire to the powered target. The target powers the level shifters.
Tigard-Powered: Set the switch to a voltage, and connect the VTGT to the unpowered target. Tigard supplies power to the target.
Self-Powered: Set the switch to a voltage, but do NOT connect the VTGT wire. Tigard powers its own level shifters. Target powers itself.

Mode Switch

This switch controls how some of the I/O pins are connected for specific uses:

When set to JTAG/SPI mode:
- All signals run straight through
- CORTEX and JTAG headers are wired for normal JTAG
- JTAG and SPI headers can be used for SPI
When set to SWD/I2C mode:
- DO and DI are wired together to create SWDIO or SDA
- CORTEX and JTAG headers can be used for SWD
- JTAG and SPI headers can be used for I2C

UART

Hookup:

In most cases, you need pins 2,3,and 4 of the UART header - Ground, TX, and RX. Connect these to your target
If you have a VCC header on your target, connect pin 1 - VTGT to it, and slide the voltage selector to VTGT
If you don't have a VCC header, leave the VTGT wire disconnected, and choose your target voltage with the selector

Software:

The first of the two ports is connected to the UART header. When you plug Tigard in, you will see two serial devices show up - the first one is the one you want. Start your software using the appropriate serial port. For example:

screen /dev/ttyUSB0 115200

SPI

Hookup:

The SPI/I2C header is laid out to be the same orientation as the pins on a standard 8-pin SPI flash chip, making it easy to attach clips or sockets.

Select SPI/JTAG on the mode selection switch
Connect your clip or socket to the header. Pay attention to pin 1, which is usually marked on sockets or has a red/highlighted wire on ribbon cables
Connect your clip to the target or insert your chip into the socket
If you're doing this in-circuit, you must take extra precautions to make sure no other device is communicating with the SPI device.
If you're using a clip in-circuit and the target is powered on, choose the VTGT option on the voltage slider
If you're using a zif socket, or clip with a powered-off target, choose the voltage on the voltage slider.

Software:

flashrom is the most common tool for SPI flash dumps. However, while pervasive, it is very slow and inefficient.

flashrom -p ft2232_spi:type=2232H,port=B,divisor=4

libmpsse is a powerful library for controlling the MPSSE, or high speed serial pins of the x232H series. However, it is no longer recommended because of a large number of dependencies

pyftdi is a new and simple interface very similar to libmpsse:

from pyftdi.ftdi import Ftdi
Ftdi.show_devices()
from os import environ
ftdi_url = environ.get('FTDI_DEVICE', 'ftdi://ftdi:2232:1:23f/2')
from spiflash.serialflash import SerialFlashManager
flash=SerialFlashManager.get_flash_device(ftdi_url)
print("Flash device: %s @ SPI freq %0.1f MHz" % (flash, flash.spi_frequency/1E6))
f=open("data.bin","wb")
f.write(flash.read(0,len(flash)))
f.close()

I2C (on I2C, SPI, or JTAG header)

Hookup:

The I2C header (on hardware versions 1.0 and later) is compatible with Sparkfun's Qwiic and Adafruit's STEMMA QT system:

Connect a 4-pin JST SH compatible cable into the I2C connector
Connect the other end to your STEMMA QT, Qwiic, or other I2C device

In addition, the SPI header is laid out to be the same orientation as the pins on most 8-pin I2C chips, making it easy to attach clips or sockets:

Connect your clip or socket to the header. Pay attention to pin 1, which is usually marked on sockets or has a red/highlighted wire on ribbon cables
Connect your clip to the target or insert your chip into the socket

Finally, the JTAG header can also be used to get the I2C signals on .1" individual pins:

Connect the 8-wire JTAG harness to the JTAG connector
Connect the white SCL and grey SDA wires to your target's I2C pins

In either case, you need to set the Tigard switches properly:

Select I2C on the mode selection switch
If you're attaching to a device in-circuit and the target has its own power, choose the VTGT option on the voltage slider
If you're attaching a standalone sensor, socket, or clip with a powered off target, choose the correct voltage on the voltage slider

Quirks:

The FT2232H has a very limited I2C implementation. I2C depends on shared I/O lines using open collector/open drain instead of push-pull-tristate I/O, but the FT2232H doesn't support that well. Therefore:

Only controller operation is supported, not Device
Tigard may not play nice if there are other controllers present on the I2C interface
Clock stretching is not supported
The I2C switch ties the DI and DO lines together so that it can do bidirectional communication
The pullup resistors are not included since they are usually located on the target, and the weak pullups on the level shifters are sufficient

Hacks:

To accomodate both I2C and SWD, the DI and DO lines are combined through resistor R16. This is required for SWD and generally acceptable for I2C.

Many I2C targets already have pullup resistors. In addition, all of Tigard's I/O pins have a weak 100K ohm pullup. In testing, this has been sufficient for both in-circuit and external use of most I2C devices. If you need stronger pullups on I2C, you can temporarily add them by pulling up COPI and SCK on the SPI header, or TCK and TDI on the JTAG header.

Software:

libmpsse is a powerful library for controlling the MPSSE, or high speed serial pins of the x232H series. However, it is no longer recommended because of a large number of dependencies

pyftdi is a new and simple interface very similar to libmpsse:

from pyftdi.ftdi import Ftdi
Ftdi.show_devices()
from os import environ
ftdi_url = environ.get('FTDI_DEVICE', 'ftdi://ftdi:2232:1:23f/2')
from i2cflash.serialeeprom import SerialEepromManager
flash = SerialEepromManager.get_flash_device(ftdi_url,'24AA32A',0x50)
flash.write(5,10)
flash.read(0,32)

JTAG Debug (on JTAG or CORTEX header)

Hookup:

The JTAG header is laid out with pins in the same order as the FTDI I/O pins are labeled, in order to be consistent with many other x232H breakout b

Tigard

Install / Use

README

Tigard

Objectives

Contents

Software Features

Hardware Features

Usage

Hardware Hookup

Switches

Voltage Switch

Mode Switch

UART

Hookup:

Software:

SPI

Hookup:

Software:

I2C (on I2C, SPI, or JTAG header)

Hookup:

Quirks:

Hacks:

Software:

JTAG Debug (on JTAG or CORTEX header)

Hookup: