The CodeWarrior USB TAP ColdFire BDM probe has a 26-pin connector which automatically supports target signal levels from 1.8V to 3.3V.
The following figure shows the pin assignments of the probe BDM connector.
The table below lists BDM signal names, direction, pin numbers, descriptions, and drive capabilities for the probe BDM connector.
| BDM pin | Signal mnemonic | Signal direction | Description |
|---|---|---|---|
| 1 | Reserved | From target system | 30pF load |
| 2 | BKPT | Bi-directional | Open-drain. 100Ohm to ground when asserted by USB TAP probe, 35pF load when not asserted1 |
| 3 | GND | - n/a - | |
| 4 | DSCLK | From USB TAP probe connector | 50mA driver |
| 5 | GND | - n/a - | |
| 6 | Reserved | - n/a - | |
| 7 | RESET | Bi-directional | Open-drain. 100Ohm to ground when asserted by USB TAP probe, 35pF load when not asserted1 |
| 8 | DSI | From USB TAP probe connector | 50mA driver |
| 9 | VDD | From target system | 2MOhm pull-down, plus 0.01uF load |
| 10 | DSO | From target system | 30pF load |
| 11 | GND | - n/a - | |
| 12 | PST3 | - n/a - | |
| 13 | PST2 | - n/a - | |
| 14 | PST1 | - n/a - | |
| 15 | PST0 | - n/a - | |
| 16 | DDATA3 | - n/a - | |
| 17 | DDATA2 | - n/a - | |
| 18 | DDATA1 | - n/a - | |
| 19 | DDATA0 | - n/a - | |
| 20 | GND | - n/a - | |
| 21 | Reserved | - n/a - | |
| 22 | Reserved | - n/a - | |
| 23 | GND | - n/a - | |
| 24 | PSTCLK | From target | 30pF load |
| 25 | Core Voltage | - n/a - | |
| 26 | TEA | - n/a - |
Note: All BDM signals must meet accepted standards for ColdFire BDM signal design. To ensure proper and stable operation between the USB TAP probe and the target, the BDM signals must meet the requirements listed in table below.
The following table provides a general description of each BDM signal and the operational requirements.
| BDM pin | Signal mnemonic | Requirement |
|---|---|---|
| 1 | Reserved | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 2 | BKPT | Must be wired to the target. |
| 3 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 4 | DSCLK | DSCLK must be connected to the target's processor. It is driven by the USB TAP probe as an output with up to 50mA. This signal is the clock for the BDM 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 USB TAP ground inside the USB TAP probe. |
| 6 | Reserved | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 7 | RESET | Must be wired to the target. During reset, the USB TAP probe drives RESET to ground through a 100Ohm resistor. |
| 8 | DSI | Must be wired to the target processor. The USB TAP probe drives the TDI output with up to 50mA. |
| 9 | VDD | Must be wired to the target. The USB TAP probe uses this signal to determine if power is applied to the target. The signal is also used as a voltage reference for the signals driven by the USB TAP probe (BKPT, DSCLK, RESET, DSI, and TEA). |
| 10 | DSO | Must be wired to the target processor. It is an input to the USB TAP probe. |
| 11 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 12 | PST3 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 13 | PST2 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 14 | PST1 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 15 | PST0 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 16 | DDATA3 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 17 | DDATA2 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 18 | DDATA1 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 19 | DDATA0 | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 20 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 21 | Reserved | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 22 | Reserved | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 23 | GND | Must be wired to the target. GND is connected directly to the ground inside the USB TAP probe. |
| 24 | PSTCLK | May be wired to the target. The USB TAP probe uses this signal to support synchronous clocking mode. |
| 25 | Core Voltage | Need not be wired to the target. The USB TAP probe does not currently use this signal. |
| 26 | TEA | Need not be wired to the target. The USB TAP probe does not currently use this signal. |