Renesas M16C/62P Series Hardware Manual page 247

M16C/62P Group (M16C/62P, M16C/62PT)
17.2.3 Functions for Setting an S
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
Signal written to
SiTRR register
SMi7 bit
SMi3 bit
SOUTi (internal)
SOUTi pin output
(i = 3, 4)
initial value to "H"
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
Rev.2.41 Jan 10, 2006
REJ09B0185-0241
http://www.xinpian.net
Port output
Initial value = H
Setting the SOUTi Port selection switching
(I/O port → SOUTi)
(2)
Page 232 of 390
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i Initial Value
OUT
(1)
D0
D0
(3)
17. Serial Interface
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)
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
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