M16C User Manual.pdf

Appendix Standard Serial I/O Mode (Flash Memory Version)Mitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTERLock Bit Disable CommandThis command disables the lock bit. The command code “7516” is sent in the 1st byte of the serialtransmission. This command only disables the lock bit function; it does not set the lock bit itself.However, if an erase command is executed after executing the lock bit disable command, “0” (locked)lock bit data is set to “1” (unlocked) after the erase operation ends. In any case, after the reset iscancelled, the lock bit is enabled.CLK1RxD1(M16C reception data)7516TxD1(M16C transmit data)RTS1(BUSY)Figure 1.31.12. Timing for disabling the lock bitDownload CommandThis command downloads a program to the RAM for execution. Execute the download command asexplained here following.(1) Send the “FA16” command code in the 1st byte of the transmission.(2) Send the program size in the 2nd and 3rd bytes of the transmission.(3) Send the check sum in the 4th byte of the transmission. The check sum is added to all data sentin the 5th byte onward.(4) The program to execute is sent in the 5th byte onward.When all data has been transmitted, if the check sum matches, the downloaded program is executed.The size of the program will vary according to the internal RAM.CLK1RxD1(M16C reception data)FA16ChecksumProgramdataProgramdataTxD1(M16C transmit data)Data size (low)Data size (high)RTS1(BUSY)Figure 1.31.13. Timing for download263