The CodeWarrior USB TAP DPI probe has a 10-pin connector which automatically supports target signal levels from 1.8V to 3.3V.
The following figure shows the pin assignments of the probe DPI connector.
The following table lists DPI signal names, direction, pin numbers, descriptions, and drive capabilities for the probe DPI Connector.
Note: All DPI signals must meet accepted standards for DPI signal design. To ensure proper and stable operation between the USB TAP probe and the target, the DPI signals must meet the requirements listed in Table B.2.
| DPI pin | Signal mnemonic | Signal direction | Description |
|---|---|---|---|
| 1 | VLSO/FRZ | From target system | 30pF load |
| 2 | SRST | Bi-directional | Open-drain. 100Ohm to ground when asserted by USB TAP probe, 35pF load when not asserted1 |
| 3 | GND | - n/a - | |
| 4 | DSCK | From USB TAP probe connector | 50mA driver |
| 5 | GND | - n/a - | |
| 6 | VFLS1/FRZ | From target system | 35pF load1 |
| 7 | HRST | Bi-directional | Open-drain. 100Ohm to ground when asserted by USB TAP probe, 35pF load when not asserted1 |
| 8 | DSDI | From USB TAP probe connector | 50mA driver |
| 9 | VDD | From target system | 2MOhm pull-down, plus 0.01uF load |
| 10 | DSDO | From target system | 30pF load |
The following table provides a general description of each DPI signal and the operational requirements.
| DPI pin | Signal mnemonic | Requirement |
|---|---|---|
| 1 | VLSO/FRZ | VFLS0/FRZ is not needed for emulation. |
| 2 | SRST | Must be wired to the target. During reset, the USB TAP probe drives SRST to ground through a 100Ohm resistor. |
| 3 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 4 | DSCK | Must be wired to the target processor. It is driven by the USB TAP as an output with up to 50mA. This signal is the clock for the DPI interface. It is good design practice to keep the trace length short and isolate the trace from other signals. If the trace must be long, then termination may be needed. |
| 5 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 6 | VFLS1/FRZ | VFLS1/FRZ is not needed for emulation. |
| 7 | HRST | Must be wired to the target. During reset, the USB TAP probe drives HRST to ground through a 100Ohm resistor. |
| 8 | DSDI | Must be wired to the target processor. The USB TAP probe drives the TDI output with up to 50 mA. |
| 9 | VDD | Must be wired to the target. The USB TAP probe uses this signal to determine if power is applied to the target. This signal is also used as a voltage reference for the signals driven by the USB TAP probe (SRST, SDCK, HRST, DSDI). |
| 10 | DSDO | Must be wired to the target processor. DSDO is an output from the target processor and an input to the USB TAP probe. It is good design practice to keep the trace length short and isolate the trace from the other signals. |