MC96FM204/FM214April 7, 2016 Ver. 1.8 145Figure 14.1 Block Diagram of On-Chip Debug System14.2 Two-Pin External Interface14.2.1 Basic Transmission Packet• 10-bit packet transmission using two-pin interface.• 1-packet consists of 8-bit data, 1-bit parity and 1-bit acknowledge.• Parity is even of ‘1’ for 8-bit data in transmitter.• Receiver generates acknowledge bit as ‘0’ when transmission for 8-bit data and its parity has no error.• When transmitter has no acknowledge (Acknowledge bit is ‘1’ at tenth clock), error process is executed intransmitter.• When acknowledge error is generated, host PC makes stop condition and transmits command which has erroragain.• Background debugger command is composed of a bundle of packet.• Start condition and stop condition notify the start and the stop of background debugger command respectively.BDCFormatconverterUSBCPUCode memory- SRAM- Flash- EEPROMData memoryDBG RegisterPeripheralUser I/OAddress busInternal data busDSDADSCLTarget MCU internal circuitDBGControl
