Detailed description
- No new features.
- The existing problem is STM32MP15x toggling all of its GPIOs unpredictably when a BMP(-compatible) platform performs an SWD scan of it with TDI wire connected.
- The PR solves it by driving TDI high not low. See JTAG spec.
Tested with blackpill-f411ce against STM32MP157 to stop toggling GPIO randomly (but in another form; via platform_init() gpio_set() call to initialize TDI pin as high). As much as I would like to tree-wide init the pins to high, doing it centrally is faster.
That SoC has a CLTAPC or BSCAN TAP (unknowable which) and a couple of errata entries for that. If TDI defaults to be driven low, then an unexpected light show happens (with some adapters) and only in SWD.
Your checklist for this pull request
- I've read the Code of Conduct
- I've read the guidelines for contributing to this repository
- It builds for hardware native (see Building the firmware)
- It builds as BMDA (see Building the BMDA)
- I've tested it to the best of my ability
- My commit messages provide a useful short description of what the commits do
Closing issues
## Detailed description
* No new features.
* The existing problem is STM32MP15x toggling all of its GPIOs unpredictably when a BMP(-compatible) platform performs an SWD scan of it with TDI wire connected.
* The PR solves it by driving TDI high not low. See JTAG spec.
Tested with `blackpill-f411ce` against STM32MP157 to stop toggling GPIO randomly (but in another form; via `platform_init()` `gpio_set()` call to initialize TDI pin as high). As much as I would like to tree-wide init the pins to high, doing it centrally is faster.
That SoC has a CLTAPC or BSCAN TAP (unknowable which) and a couple of errata entries for that. If TDI defaults to be driven low, then an unexpected light show happens (with *some* adapters) and only in SWD.
## Your checklist for this pull request
* [x] I've read the [Code of Conduct](https://codeberg.org/blackmagic-debug/blackmagic/src/CODE_OF_CONDUCT.md)
* [x] I've read the [guidelines for contributing](https://codeberg.org/blackmagic-debug/blackmagic/src/CONTRIBUTING.md) to this repository
* [x] It builds for hardware native (see [Building the firmware](https://codeberg.org/blackmagic-debug/blackmagic?tab=readme-ov-file#building-the-firmware))
* [x] It builds as BMDA (see [Building the BMDA](https://codeberg.org/blackmagic-debug/blackmagic?tab=readme-ov-file#building-black-magic-debug-app))
* [ ] I've tested it to the best of my ability
* [x] My commit messages provide a useful short description of what the commits do
## Closing issues