- /* Lower direction change guard time to 0 USART bits */
- XPROGTarget_SendByte(PDI_CMD_STCS | PDI_CTRL_REG);
- XPROGTarget_SendByte(0x07);
-
- /* Enable access to the XPROG NVM bus by sending the documented NVM access key to the device */
- XPROGTarget_SendByte(PDI_CMD_KEY);
- for (uint8_t i = sizeof(PDI_NVMENABLE_KEY); i > 0; i--)
- XPROGTarget_SendByte(PDI_NVMENABLE_KEY[i - 1]);
-
- /* Wait until the NVM bus becomes active */
- NVMBusEnabled = XMEGANVM_WaitWhileNVMBusBusy();
- }
- else
- {
- /* Enable TPI programming mode with the attached target */
- XPROGTarget_EnableTargetTPI();
-
- /* Lower direction change guard time to 0 USART bits */
- XPROGTarget_SendByte(TPI_CMD_SSTCS | TPI_CTRL_REG);
- XPROGTarget_SendByte(0x07);
-
- /* Enable access to the XPROG NVM bus by sending the documented NVM access key to the device */
- XPROGTarget_SendByte(TPI_CMD_SKEY);
- for (uint8_t i = sizeof(TPI_NVMENABLE_KEY); i > 0; i--)
- XPROGTarget_SendByte(TPI_NVMENABLE_KEY[i - 1]);
-
- /* Wait until the NVM bus becomes active */
- NVMBusEnabled = TINYNVM_WaitWhileNVMBusBusy();
- }
-
- Endpoint_Write_Byte(CMD_XPROG);
- Endpoint_Write_Byte(XPRG_CMD_ENTER_PROGMODE);
- Endpoint_Write_Byte(NVMBusEnabled ? XPRG_ERR_OK : XPRG_ERR_FAILED);