M16C6S_09 Datasheet, PDF (197/208 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

M16C/6S Group
Usage Notes
UART Mode
Special Mode 1 (I²C bus Mode)
When generating start, stop and restart conditions, set the STSPSEL bit in the U2SMR4 register to 0 and
wait for more than half cycle of the transfer clock before setting each condition generate bit (STAREQ,
RSTAREQ and STPREQ) from 0 to 1.
SI/O3, SI/O4
The SOUTi default value which is set to the SOUTi pin by the SMi7 bit approximately 10ns may be output
when changing the SMi3 bit from 0 (I/O port) to 1 (SOUTi output and CLKfunction) while the SMi2 bit in
the SiC (i=3 and 4) to 0 (SOUTi output) and the SMi6 bit is set to 1 (internal clock). And then the SOUTi
pin is held high-impedance.
If the level which is output from the SOUTi pin is a problem when changing the SMi3 bit from 0 to 1, set the
default value of the SOUTi pin by the SMi7 bit.
Programmable I/O Ports
The input threshold voltage of pins differs between programmable input/output ports and peripheral func-
tions.
Therefore, if any pin is shared by a programmable input/output port and a peripheral function and the
input level at this pin is outside the range of recommended operating conditions VIH and VIL (neither
“high” nor “low”), the input level may be determined differently depending on which side—the program-
mable input/output port or the peripheral function—is currently selected.
Rev.5.01 Dec 10, 2009 page 197 of 201
REJ03B0014-0501