software JTAG mode

[Baldanos]

Software JTAG for Hydrabus.

This is a first implementation of the JTAG protocol for the HydraBus

Features :

• Classic JTAG (TDI/TDO/TMS/TCK)
• Can be used with command line
• BusPirate-compatible OpenOCD binary mode ( openocd command)
• Can scan a JTAG bus with IDCODE and BYPASS methods ( idcode and bypass commands)
• Can try to find JTAG bus on all GPIOB pins (like JTAGulator) ( brute command)

TODO:

• Enhance port speed
• Enhance binary mode
• Add support for TRST
• Add support for MSB/LSB when reading

[bvernoux]

There is infinite loop problems when system does not answer example:
jtag_scan_bypass & tag_scan_idcode => It shall check regularly => if(USER_BUTTON) to returns (to avoid infinite loop) to be checked if there is other case to avoid infinite loop.
Also my test with LPC4330 show that scan_bypass & scan_idcode does not returns anything (but it could be specific to case of LPC43xx) I will check with other MCU/Devices with JTAG.

Could you tell on which MCU/CPU the code has been tested and is working ? (and which function ?)