Open-TL866

Open-TL866 is open-source firmware for the original TL866 (i.e., not II / PLUS). This firmware replaces the proprietary firmware for programming EPROMs, MCUs, GALs, etc. Note that this firmware is not meant to be a replacement for the original firmware, it is totally different with a different purpose. You can't use a TL866 programmed with this firmware with the original TL866 host software. This firmware exposes a simple ASCII-based interface over USB serial. This repository contains two primary components.

1. An open-source firmware for the TL866 (Located in the firmware directory).
2. A Python library for interacting with open-source firmware (Located in the py directory).

Caution: This is alpha software. Use at your own risk.

Python Bitbang Quick Start

FIXME 2022-11-02: we've made a breaking change. You'll need a new firmware release. In the meantime use git.

Do you just want to send low level TL866 commands from Python? This is useful if you have loose timing requirements.

Linux instructions:

git clone https://github.com/JohnDMcMaster/open-tl866.git && \
cd open-tl866 && \
( cd py && python3 setup.py install --user ) && \
wget https://github.com/JohnDMcMaster/open-tl866/releases/download/v0.0/tl866-bitbang.hex && \
otl866 self update tl866-bitbang.hex

Now test it: python3 py/example/blinky.py

Building the Firmware

Building may be performed natively or via Docker. Regardless, there is a single common prerequisite: downloading Git submodules. Install them with git submodule update --init.

• our copy of m-stack
• cmake-microchip

If one wishes to build natively, then install the following prerequisites:

1. The XC8 compiler from Microchip is used to compile our C code. Currently version 1.x is required. Download it from Microchip's site and install it. When activating, select the Free version.

   Note: If you are installing to a 64-bit Ubuntu distribution, you must first get the 32-bit libc that isn't installed by default: sudo apt-get install libc6:i386. Then you can run Microchip's installer.

2. CMake is needed to generate the build configuration. On Linux you should install it from your distribution's package manager (e.g. sudo apt-get install cmake). For Windows, an installer is available from the CMake website.

Building

make build

To make any Make target with docker, prefix it with docker-. For instance, to build with Docker:

make docker-build

Flashable images are in firmware/build/dist/tl866-*.hex

The build configuration is maintained with CMake in CMakeLists.txt. Calling cmake . interprets the CMake configuration and produces a set of makefiles in the source tree. If you prefer an out-of-source build, just call cmake from the directory where you want the build output and pass it the path to the firmware directory.

There are multiple variants of the firmware with different functionality, which are currently called "modes". Each mode produces a separate firmware image under firmware/dist. Each mode has a corresponding target in the makefiles, so you can build just one mode with e.g. make tl866-bitbang. The currently implemented modes are:

Mode	Description
tl866-bitbang	This mode is for generic pin control from Python via a serial interface
tl866-at89	This mode is for reading and writing the AT-Atmel AT89S

Device Drivers and Configuration

On Linux systems, the udev rules file contrib/96-opentl866.rules should be copied into /etc/udev/rules.d/. Doing so will allow non-root users who are members of the plugdev group to access the devices. Once the rules file is installed udev needs to be reloaded. On modern Linux systems that use systemd, that can be done by running:

sudo systemctl restart systemd-udevd

Programming

The Python client library provides a command-line client for the stock bootloader which can be used to flash any firmware to the TL866. To install the CLI tool, run:

( cd py && python3 setup.py install --user )

And then TLDR: otl866 self update firmware/build/dist/tl866-bitbang.hex

If that doesn't work, read on.

Resetting to the Bootloader

The first step in flashing any firmware is to get the TL866 to reboot into its bootloader. How exactly you need to go about that depends on which firmware your TL866 is currently running.

From the Stock Firmware

If your TL866 is running an older version of the stock firmware the update tool can request a reset into the bootloader without any help. If you have version 03.2.85 or newer of the stock firmware there's currently a bug that prevents that from working, so you'll need to use the hardware method below.

From the Open Firmware

If your TL866 is running the open firmware the update tool can trigger a reset into the bootloader: otl866 self update firmware/dist/tl866-epromv.hex On Windows or if you multiple serial ports you may need to add --reset-tty(ex: --reset-tty COM6 on Windows)

If you flashed the open firmware onto the TL866 using a separate ICSP programmer the bootloader has been erased from your TL866. Do not reprogram a TL866's firmware using the ICSP connector on the same TL866. In order to use the update tool you'll need to flash the stock firmware via ICSP to restore the bootloader. You can find ICSP-ready images of the stock firmware in Radioman's repository.

The Hardware Method

If you're having trouble resetting to the bootloader from within the firmware currently installed on your TL866, you can force it to boot into the bootloader by shorting pin RC1 of the microcontroller to Vcc while you plug it in to the USB. The easiest points to short with a piece of jumper wire are from pin 2 of J1 (the ICSP header) or the tab of the adjacent voltage regulator to the side of R26 nearest J1.

If you find yourself using this method frequently it can be worthwhile to solder a mini tactile switch between R26 and the side of R2 nearest the edge of the board. That side of R2 is also Vcc and is much closer to R26 than the voltage regulator is.

Flashing the Open Firmware

To flash the open firmware, open a command prompt and navigate to the folder where you built the firmware. Call the update tool, passing it the path to the Intel Hex file. If your TL866 is already running the stock firmware you'll also need the --reset-tty option (see above).

otl866 self update --reset-tty COM6 dist/default/production/firmware.production.hex

Flashing the Stock Firmware

The update tool can also flash the stock firmware. To do so you'll need the update.dat file from the official software. If you installed it with the default settings that should be at C:\MiniPro\update.dat. You'll need to pass the --stock option to tell the updater that you want to flash the stock firmware, and you'll also need to use the --reset-tty option if your TL866 is running the open firmware.

otl866 self update --reset-tty COM6 --stock C:\MiniPro\update.dat

Flashing During Development

The above programming instructions apply to users only of the firmware and assume the code protection bit of the TL866 PIC is enabled.

For doing development of open-tl866, an external ICSP programmer such as PICkit is highly recommended to get access to debugging features. All open firmware images generated by open-tl866 are placed in the microcontroller's memory after the bootloader. A developer wishing to selectively reprogram and debug the payload must disable code protection beforehand.

Code protection disable is ICSP is implemented as a full erase of the microcontroller's address space, including the bootloader. Radioman's TL866 Updater is capable of generating a full firmware image, including a bootloader, with code protection disabled, which should be flashed onto TL866 using an external ICSP programmer.

At this point, as user should be able to use an external ICSP programmer to reprogram an open-tl866 payload (Radioman's Updater provides a stock payload), all while leaving the bootloader intact. Debug facilities should also be available from the ICSP programmer.

Due to a bug mentioned before, the stock firmware is incapable of resetting back to the bootloader if code protection is disabled; the open firmwares do not have this problem.

Running

The TL866 with the open firmware will identify itself as a serial port (USB CDC). A Python library is provided which makes it easy to drive the bitbang mode.

Bitbang CLI examples

CMD> ?
open-tl866 (bitbang)
VPP
E val      VPP: enable and/or disable (VPP_DISABLE/VPP_ENABLE)
V val      VPP: set voltage enum (VPP_SET)
p val      VPP: set active pins (VPP_WRITE)
VDD
e val      VDD: enable and/or disable (VDD_DISABLE/VDD_ENABLE)
v val      VDD: set voltage enum (VDD_SET)
d val      VDD: set active pins (VDD_WRITE)
GND
g val      GND: set active pins (GND_WRITE)
I/O
t val      I/O: set ZIF tristate setting (ZIF_DIR)
T          I/O: get ZIF tristate setting (ZIF_DIR_READ)
z val      I/O: set ZIF pins (ZIF_WRITE)
Z          I/O: get ZIF pins (ZIF_READ)
Misc
L val      LED on/off (LED_ON/LED_OFF)
m z val    Set pullup/pulldown (MYSTERY_ON/MYSTERY_OFF}
s          Print misc status
i          Re-initialize
b          Reset to bootloader (RESET_BOOTLOADER)

With that in mind...

Blink the yellow LED:

CMD> L 1
CMD> L 0

Set pin 1 to 5.1V via VDD:

# Enable all (possible) VDD outputs
d 0000000001
# Voltage enum 3 => 5.1V (see aclient.py)
v 3
# Enable VDD
e 1

Set all pins logic low using I/O except 1) pin 1 is tristated 2) pin 2 to logic high:

z 0000000002
t 0000000001

Version history

v0.0

• I believe this is where the 0.0 release .hex comes from, but TBH it was just random file "known to work"

v0.1 (future)

• bitbang: zif format string endianess changed. Pin 1 went from 0100000000 to 0000000001
• read_rom added (82S129, 74S287, 63S281, 74LS471)
• In support of mega866 (https://github.com/JohnDMcMaster/mega866-src) * Small bug fixes