10.1 Four-Wire Interface

The following steps are required to enter Serial Execution mode:
Note: The assumption is that the MCLR pin has been driven low from the previous check device status step (see Figure 8-1).
  1. SendCommand (MTAP_SW_MTAP).
  2. SetMode (6’b011111).
  3. SendCommand (MTAP_COMMAND).
  4. statusVal = XferData (MCHP_STATUS).
  5. If CPS (statusVal[7]) is not ‘1’, first, erase the device.
  6. SendCommand (MTAP_SW_ETAP).
  7. SetMode (6’b011111).
  8. SendCommand (ETAP_EJTAGBOOT).
  9. Set the MCLR pin high.