A little program I made to be able to program my MSP430 MCU out of the box, without needing any FET adapters or specific hardware - only USB to UART adapters.

[!hot] It's only a few kilobytes

To be able to interact with the MSP430 BootStrap Loader (BSL) on the UART bus via TX & RX, we must invoke the BSL by a special sequence on #RST & TEST pins. Even though not officially supported on all models, the documentation writes about it by using #DTR & #RTS (they are both standard serial output signals that we can toggle manually)

Technically, any USB to UART (Serial) adapter with #DTR & #RTS lines can do the job. A non-exhaustive list of the most common chips:

• tested
  • FTDI
    • FT232H - https://ftdichip.com/products/ft232hq/ - my favorite as it supports SPI communication with many memory chips
    • FT232R - https://ftdichip.com/products/ft232rq/
  • WCH (Jiangsu Qin Heng)
    • CH340K - https://www.wch.cn/products/CH340.html
    • CH343P - https://www.wch.cn/products/CH343.html
  • Silicon Labs
    • CP2102 - https://www.silabs.com/interface/usb-bridges/classic/device.cp2102
• not tested
  • Prolific
    • PL2303 - https://www.prolific.com.tw/US/ShowProduct.aspx?pcid=41
  • Microchip
    • MCP2200 - https://www.microchip.com/en-us/product/MCP2200
    • MCP2221A - https://www.microchip.com/en-us/product/MCP2221A

[!tip] You can find many USB adapters with these chips for a few €/$ on AliExpress/Amazon

[!warning] Check if your USB adapter supports the required I/O voltage (+3.3V) and provides pins for all necessary signals, especially #DTR Some adapter manufacturers do not make all chip signals available to the user

All of them can be used with the basic Windows API for communication: https://learn.microsoft.com/windows/win32/devio/communications-functions, especially with EscapeCommFunction to drive #DTR & #RTS.

In msp430_kibsl, you can use them out-of-the box with the integrated serial (default) driver, by specifying the COM port number on the command line

> msp430_kibsl /port:com17 /elf:st25tb_kiemul.out
[...]
Selected driver: serial
Using serial port: com17 (\\.\com17)...: OK
  0 | <ignored>
  1 | <ignored>
  2 | 0x8000 - 0xa92f ( 10544) ..........................................OK - CRC16 OK (4d1b)
[...]

But what if you have an adapter without #DTR? Or if you don't want to use #DTR & #RTS because they interfere with UART communication when not flashing?

https://ftdichip.com/products/umft234xd-01/ (based on https://ftdichip.com/products/ft234xd/ ) - CB0 available on chip & the adapter

[!note] The driver used with msp430_kibsl is ft234xd

> msp430_kibsl /driver:ft234xd /elf:st25tb_kiemul.out
[...]
Selected driver: ft234xd
D2XX 3.2.16
| Port available @ COM36
| Manufacturer: FTDI (FT)
| Description : UMFT234XD
| SerialNumber: FTA4O6Q2

| CBUS configuration :
  CBUS0: 0x00 (TRISTATE) - KO, needed: 0x08 (IOMODE) -- will try to adjust it
| EEPROM program  : OK
| Cycle port      : OK
| Close old handle: OK
 -- wait 5s ... --
| Re-open device  : OK
| CBUS configuration :
  CBUS0: 0x08 (IOMODE) - OK
  0 | <ignored>
  1 | <ignored>
  2 | 0x8000 - 0xa92f ( 10544) ..........................................OK - CRC16 OK (4d1b)
[...]

https://ftdichip.com/products/umft230xb-01/ (based on https://ftdichip.com/products/ft230xq/ ) - CB0 & CB1 available on the adapter

[!note] The driver used with msp430_kibsl is umft230xb

> msp430_kibsl /driver:umft230xb /elf:st25tb_kiemul.out
[...]
Selected driver: umft230xb
D2XX 3.2.16
| Port available @ D2XX Direct
| Manufacturer: FTDI (FT)
| Description : UMFT230XB
| SerialNumber: FTA2NHUZ

| CBUS configuration :
  CBUS0: 0x00 (TRISTATE) - KO, needed: 0x08 (IOMODE) -- will try to adjust it
  CBUS1: 0x00 (TRISTATE) - KO, needed: 0x08 (IOMODE) -- will try to adjust it
| EEPROM program  : OK
| Cycle port      : OK
| Close old handle: OK
 -- wait 5s ... --
| Re-open device  : OK
| CBUS configuration :
  CBUS0: 0x08 (IOMODE) - OK
  CBUS1: 0x08 (IOMODE) - OK
  0 | <ignored>
  1 | <ignored>
  2 | 0x8000 - 0xa92f ( 10544) ..........................................OK - CRC16 OK (4d1b)
[...]

[!note] Received dongles were in D2XX Direct configuration, without a virtual COM port not important to interract with msp430_kibsl, but you may change its configuration with FT Prog

• Programmers and debuggers
• https://www.ti.com/lit/pdf/slau550