When external trace output is used the output signals must be assigned to appropriate package pins.
The
RISC-V Trace Connector Specification, Version 1.0, defines two connectors:
As an example, the nominal assignment for the KC-705 board when using the
AMD FMC
XM105 Debug Card to connect the trace signals to the Mictor connector are
listed in the following table. The FMC HPC connector pins are also listed, which allows
deriving the pin assignment for other boards using the same FMC connector and debug
card.
- MIPI20 Debug and Trace Connector
- Mictor 38-bit Debug and Trace Connector
| KC705 | FMC HPC Pin Name | Mictor Pin Number | ||
|---|---|---|---|---|
| Signal | Pin | IOB | ||
| TRACE_clk_o | C25 | No | LA00_CC_P | 6 |
| TRACE_ctl | C30 | Yes | LA10_N | 36 |
| TRACE_data[0] | D29 | Yes | LA10_P | 38 |
| TRACE_data[1] | H27 | Yes | LA03_N | 28 |
| TRACE_data[2] | G28 | Yes | LA04_P | 26 |
| TRACE_data[3] | F28 | Yes | LA04_N | 24 |
| TRACE_data[4] | B30 | Yes | LA09_P | 22 |
| TRACE_data[5] | A30 | Yes | LA09_N | 20 |
| TRACE_data[6] | D26 | Yes | LA01_CC_P | 18 |
| TRACE_data[7] | C26 | Yes | LA01_CC_N | 16 |
| TRACE_data[8] | G29 | Yes | LA05_P | 37 |
| TRACE_data[9] | F30 | Yes | LA05_N | 35 |
| TRACE_data[10] | H30 | Yes | LA06_P | 33 |
| TRACE_data[11] | G30 | Yes | LA06_N | 31 |
| TRACE_data[12] | E28 | Yes | LA07_P | 29 |
| TRACE_data[13] | D28 | Yes | LA07_N | 27 |
| TRACE_data[14] | E29 | Yes | LA08_P | 25 |
| TRACE_data[15] | E30 | Yes | LA08_N | 23 |
| Logic 0 = 0V | H26 | No | LA03_P | 30 |
| Logic 0 = 0V | H25 | No | LA02_N | 32 |
| Logic 1 = 1.8V | H24 | No | LA02_P | 34 |
The IOB column indicates pins where it is recommended to add
a constraint to place the output flip-flop in the pad to minimize skew. The
parameter C_TRACE_OUTPUT should be set to 1 and
C_TRACE_DATA_WIDTH should be set to 16 with
this pin assignment.