Fix: STM32WL55 discovery #2048
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Fix: STM32WL55 discovery #2048
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…alue used for multi-drop SWD protocol recovery
…o address a protocol recovery issue seen with the STM32WL55
…tsel` value used for multi-drop SWD protocol recovery
…ks as it was causing a faulting CTRL/STAT read to be ignored and the debugger to claim no errors occured
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Detailed description
In this PR we address issues found while trying to debug STM32WL55 discovery. This process found bugs in both the error recovery implementation for SWD, and in the remote protocol.
On the SWD side, the error detection code failed to properly notice when a read of the DP's CTRL/STAT register failed and then properly handle that with protocol recovery. This slightly complicates the routine, but makes the error discovery and recovery process significantly more robust.
On the remote protocol side, the protocol failed to transfer the TARGETSEL value to use for a given DP for SWD multi-drop, resulting in protocol recovery failing to execute correctly to re-select the target and resume communications. This is corrected by addition of a new command for transferring this information to the shadow DP the probe maintains. Users running firmware from before this point will get a neat message displayed from BMDA informing them of the need to upgrade their firmware.
Your checklist for this pull request
Closing issues
Fixes #2033