4 ms·
JTAG is hard to do. RP PIO (USB FS), TI PRU (bad toolchains), or NXP FlexIO are really required to do it correctly (or you can do it "okay" with a capable SPI c
by 15155 3y ago
JTAG is hard to do. RP PIO (USB FS), TI PRU (bad toolchains), or NXP FlexIO are really required to do it correctly (or you can do it "okay" with a capable SPI controller.)
- hkwerf 3y agoCould you explain why? A JTAG master seems easily bit-bangable unless you require high data rates?
- 15155 3y agoTMS is hard to manage. High data rates are exactly the issue. Any MCU can bitbang JTAG at 100kHz. Try doing it at 30 MHz sustained.
- bogantech 3y agoIndeed my understanding is that it should not require crazy hardware requirements - it's a serial protocol clocked by the programmer. Here's an Arduino project to program CPLDS/FPGAs using XSVF files https://github.com/wschutzer/xsvfduino https://github.com/wschutzer/xsvfduino I'd say that the cheap programming cables are abundant and already compatible with the vendor tools so there's not much motivation to reinvent the wheel.
- gaudat 3y agoFT2232H with libMPSSE. It is even advertised as a USB-to-JTAG chip.
- 15155 3y agoTerrible drivers, pinouts, etc. for the ridiculous price of $6-10.
- bvan 3y agoWhatever happened to the Jtagulator? It no longer seems to be available.