M16C62P_06 Datasheet, PDF (247/421 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

M16C/62P Group (M16C/62P, M16C/62PT)
17. Serial Interface
17.2.3 Functions for Setting an SOUTi Initial Value
If the SMi6 bit in the SiC register = 0 (external clock), the SOUTi pin output can be fixed high or low when not
transferring. However, the last bit value of the former data is retained between data and data when transmitting
the continuous data. Figure 17.43 shows the timing chart for setting an SOUTi initial value and how to set it.
(Example) When “H” Selected for SOUTi Initial Value ⁽¹⁾
Signal written to
SiTRR register
SMi7 bit
Setting of the initial value of SOUTi
output and starting of transmission/
reception
Set the SMi3 bit to “0”
(SOUTi pin functions as an I/O port)
SMi3 bit
D0
SOUTi (internal)
Port output
D0
SOUTi pin output
Initial value = H ⁽³⁾
(i = 3, 4)
Setting the SOUTi Port selection switching
initial value to “H” ⁽²⁾ (I/O port → SOUTi)
NOTES:
1. This diagram applies to the case where the bits in the SiC register are set as follows:
SMi2 = 0 (SOUTi output), SMi5 = 0 (LSB first) and SMi6 = 0 (external clock)
2. SOUTi can only be initialized when input on the CLKi pin is in the high state if the
SMi4 bit in the SiC register = 0 (transmit data output at the falling edge of the transfer clock)
or in the low state if the SMi4 bit = 1 (transmit data output at the rising edge of the
transfer clock).
3. If the SMi6 bit = 1 (internal clock) or if the SMi2 bit = 1 (SOUT output disabled),
this output goes to the high-impedance state.
Figure 17.43 SOUTi’s Initial Value Setting
Set the SMi7 bit to “1”
(SOUTi initial value = H)
Set the SMi3 bit to “1”
(SOUTi pin functions as
SOUTi output)
“H” level is output
from the SOUTi pin
Write to the SiTRR register
Serial transmit/reception starts
Rev.2.41 Jan 10, 2006 Page 232 of 390
REJ09B0185-0241