M16C Datasheet, PDF (253/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M16C / 6N Group
Standard Serial I/O Mode
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Lock Bit Disable Command
This command disables the lock bit. It functions in the same way as the WP pin in the parallel I/O mode.
The command code "7A16" is sent in the first byte of the serial transmission. This command enables the
lock bit function only; 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 will be set to "1" (unlocked) after the
erase operation ends. In any case, after the reset is cancelled, the lock bit is enabled.
CLK1
TxD1
RxD1
7516
RTS1(BUSY)
Figure 25-11. Timing for disabling the lock bit
Download Command
This command downloads a program into the RAM for execution. Execute the download command as
explained below.
(1) Send the "FA16" command code in the first byte of the transmission.
(2) Send the program size in the second and the third bytes of the transmission.
(3) Send the check sum in the fourth byte of the transmission. The check sum is added to all the data
in the fifth byte onward.
(4) The program to execute is sent in the fifth byte onward.
When all the data are transmitted, if the check sum matches, the download program is executed.
The size of the program may vary according to the internal RAM.
CLK1
TxD1
RxD1
FA16
Data size (low)
Check
sum
Program ^Program
data
data
Data size (high)
RTS1(BUSY)
Figure 25-12. Timing for download
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