Fix JTAG signals to comply with uTCA spec.
AMC specification clearly states a few requirements that aren't met by current AFC. I'll list all requirements:
- JTAG supporting AMC Modules shall provide a 10 KΩ pulldown for TCK to Logic Ground.
- JTAG supporting AMC Modules shall provide a 10 KΩ pullup for TMS to 3.3V derived from the Payload Power
- JTAG supporting AMC Modules shall provide a 10 KΩ pulldown to Logic Ground for TRST#.
- JTAG supporting AMC Modules shall provide a 10 KΩ pull up for TDI to 3.3V derived from the Payload Power.
- JTAG supporting AMC Modules shall provide signal buffering for TCK,
TMS, TRST#, and TDI. The signal length from the Connector to the buffer
shall not exceed 100 mm.
- JTAG supporting AMC Modules shall provide an individual driver for
TDO with a series terminating resistor at the driver as required by the
driving buffer output characteristics.
Fulfilling these criteria isn't straightforward:
- TRST# signal should have a pullup (as it is now), otherwise it may
not work with Xilinx JTAG which doesn't use TRST#
- if SCANSTA112 is to be powered by 3V3_MP, these pullups should also
be powered by 3V3_MP instead of payload power