M30222 Datasheet, PDF (205/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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Specifications in this manual are tentative and subject to change
MITSUBISHI MICROCOMPUTERS
M30222 Group
Rev. G
Serial I/O Mode 1 (Flash Memory Version)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Standard serial I/O mode
The standard serial I/O mode inputs and outputs the software commands, addresses and data needed to
operate (read, program erase, etc.) the internal flash memory. There are two standard serial I/O modes
that require a purpose specific peripheral unit.
• Serial I/O Mode 1 is synchronized
• Serial I/O Mode 2 is as asynchronized
The standard serial I/O mode is different from the parallel I/O mode because it uses the CPU rewrite
mode to control flash memory rewrite, rewrite data input and so on. It is started when the reset is re-
leased. This is done when the P50 (CE) pins is “H” level, the P55 (EPM) pin “L” level and the CNVss pin
“H” level. In an ordinary command mode, the CNVss pin is set to “L” level.
This control program is written in the boot ROM area when the product is shipped from Mitsubishi. Please
note that the standard serial I/O mode cannot be used if the boot ROM area is rewritten in parallel I/O
mode. In standard serial I/O mode, only the user ROM area (see Figure 1.181) can be rewritten. The boot
ROM cannot.
Also, a 7-byte ID code is used. When there is data in the flash memory, commands sent from the periph-
eral unit are not accepted unless the ID code matches.
Figure 1.161 shows the pin connections for the standard serial I/O mode. Serial data I/O uses UART1
and transfers the data serially in 8-bit units. Standard serial I/O switches between mode 1 and mode 2
according to the level of CLK1 pin when the reset is released.
Serial I/O Mode 1
To use standard serial I/O mode 1, set the CLK1 pin to “H” level and release the reset. The operation
uses the four UART1 pins CLK1, RxD1, TxD1 and RTS1 (BUSY). the CLK1 pin is the transfer clock
input pin through which an external transfer clock is input. The TxD1 pin is for CMOS output. the RTS1
(BUSY) pin outputs an “L” level when ready for reception and “H” level when reception starts.
Serial I/O Mode 2
To use standard serial I/O mode 2, set the CLK1 pin to “L” level and release the reset. The operation
uses the two UART1 pins RxD1 and TxD1.
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