M16C62 Datasheet, PDF (220/231 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Appendix Standard Serial I/O Mode
Mitsubishi microcomputers
M16C / 62 Group (80-pin)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Lock Bit Disable Command
This command disables the lock bit. The command code “7516” is sent in the 1st byte of the serial
transmission. 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 is
cancelled, the lock bit is enabled.
CLK1
RxD1
(M16C reception data)
7516
TxD1
(M16C transmit data)
RTS1(BUSY)
Figure 1.25.11. Timing for disabling the lock bit
Download Command
This command downloads a program to the RAM for execution. Execute the download command as
explained 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 sent
in 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.
CLK1
RxD1
(M16C reception data)
TxD1
(M16C transmit data)
RTS1(BUSY)
FA16
Data size (low)
Check Program ^Program
sum
data
data
Data size (high)
Figure 1.25.12. Timing for download
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