Functions For Setting An Souti Initial Value - Renesas M16C FAMILY series Hardware Manual

M 1 6 C 2 / 8 G o r u p ( M 1 6 C
14.2.3 Functions for Setting an S
If the SMi6 bit in SiC register is set to 0 (external clock), the S
when not transferring data. However, when transmitting data consecutively, the last bit (bit 0) value of the
last transmitted data is retained between the sccessive data transmissions. Figure 14.39 shows the
timing chart for setting an S
(Example) When "H" selected for S
Signal written to
SiTRR register
SMi7 bit
SMi3 bit
S i (internal)
OUT
Port output
S i pin output
OUT
(i = 3, 4)
Setting the S
initial value to "H"
(2)
NOTES:
1. This diagram applies to the case where the bits in the SiC register are set as follows:
SMi2=0 (S i output), SMi5=0 (LSB first) and SMi6=0 (external clock)
OUT
2. S i can only be initialized when input on the CLKi pin is in the high state if the SMi4bit in the
OUT
SiC register is set to "0" (transmit data output at the falling edge of the transfer clock) or
in the low state if the SMi4 bit is set to "1" (transmit data output at the rising edge of the
transfer clock).
3. If the SMi6 bit is set to "1" (internal clock) or if the SMi2 bit is set to "1" (S
this output goes to the high-impedance state.
Figure 14.39 S
OUT
R e . v 2 0 . 0 J a . n 3 , 1 2 0 0 7
R E J 0 9 B 0 0 4 7 0 - 2 0 0
2 / , 8 M 1 6 C 2 / 8 ) B
initial value and how to set it.
OUTi
(1)
i initial value
OUT
Initial value = "H"
i
Port selection switching
OUT
(I/O port S i)
OUT
i Initial Value Setting
page 216
f o 3 8 5
i Initial Value
OUT
OUTi
D0
D0
(3)
output disabled),
OUT
pin output level can be fixed high or low
Setting of the initial value of S
output and starting of transmission/
reception
Set the SMi3 bit to "0"
(S i pin functions as an I/O port)
OUT
Set the SMi7 bit to "1"
(S i initial value = "H")
OUT
Set the SMi3 bit to "1"
(S i pin functions as S
OUT OUT
"H" level is output
from the S
Write to the SiTRR register
Serial transmit/reception starts
14. Serial I/O
i
OUT
i output)
i pin
OUT