M16C6K9 Datasheet, PDF (276/292 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6K9 Group
Standard Serial I/O Mode
Standard serial I/O mode
The standard serial I/O mode inputs and outputs the S/W commands, addresses and data needed to operate
(read, program, erase etc.) the on-chip flash memory with a dedicated serial programmer.
Different from parallel I/O mode, in standard serial mode, CPU controls the flash memory reprogramming
(uses the CPU reprogram mode) and the input of serial reprogram data etc. The standard serial I/O mode is
started by connecting M0 to “H”, M1 to “L” and applying 3.0V to 3.6V externally to FVCC with the release of
reset. (To connect M0 to “L” in normal microcomputer mode.)
This control program is written in boot ROM area when the product is shipped from Renesas factory. Make
sure that the standard serial I/O mode cannot be used if boot ROM area is written in parallel I/O mode. Fig
EE-1 shows the pin connections for standard serial I/O mode. The input and output of serial data are processed
in CLK10, RxD10, TxD10, RTS10 (BUSY) 4 pins of the UART1.
The CLK10 is clock input pin, which clock is input externally. The TxD10 is CMOS output pin. The RTS10
(BUSY) pin outputs “L” when ready for reception and outputs “H” when reception starts. The serial data are
transferred in 8-bit unit.
In standard serial I/O mode, only the user ROM area shown in Fig.AB-1 can be reprogrammed. Boot ROM
area cannot be reprogrammed.
In the standard serial I/O mode, a 7-byte ID code is used. If the flash memory is not blank, commands sent
from programmer are not accepted unless the ID code matches.
Rev.1.00 Jun 06, 2003 page 276 of 290