M16C6S_09 Datasheet, PDF (179/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Flash Memory Version
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 using the serial I/O port UART1. The serial
I/O mode transfers the data serially in 8-bit units.
In the standard serial I/O mode the CPU executes a control program for flash memory rewrite (using the
CPU's rewrite mode), rewrite data input and so forth. It is started when both the P15 (CE) pin and the
CNVss pin are in “H” level after the reset is released. (In normal operation mode, set CNVss pin to “L”
level.) The main clock f1 is 5.12 MHz in this mode.
This control program is written in the boot ROM area when the product is shipped.
There are actually two standard serial I/O modes: mode 1, which is clock synchronized, and mode 2, which
is asynchronized. Standard serial I/O switches between mode 1 (clock synchronous) and mode 2 (clock
asynchronous) depending on the level of CLK1 pin when the reset is released.
To use standard serial I/O mode 1 (clock synchronous), 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 an “H” level when reception starts.
In mode 1, be sure the TxD1 (P67) pin is at high before reset being deasserted.
To use standard serial I/O mode 2 (clock asynchronous), set the CLK1 pin to “L” level and release the
reset. The operation uses the two UART1 pins RxD1 and TxD1.
In standard serial input/output mode, the user ROM area can be rewritten while the microcomputer is
mounted on-board by using a serial programmer suitable for the M16C/62P group. For more information
about serial programmers, contact the manufacturer of your serial programmer. For details on how to use,
refer to the user’s manual included with your serial programmer.
Table 1.22.1 lists pin functions (flash memory standard serial input/output mode). Figures 1.22.1 to 1.22.2
show pin connections for serial input/output mode.
ID Code Check Function
This function determines whether the ID codes sent from the serial programmer and those written in the
flash memory match. (Refer to the description of the functions to inhibit rewriting flash memory version.)
Rev.5.01 Dec 10, 2009 page 179 of 201
REJ03B0014-0501