Functions For Setting An Souti Initial Value - Renesas M16C/29 Series User Manual

M 1 6 C 2 / 9 G o r u p
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
( E x a m p l e ) W h e n " H " s e l e c t e d f o r S
S i g n a l w r i t t e n t o
S i T R R r e g i s t e r
S M i 7 b i t
S M i 3 b i t
S i ( i n t e r n a l )
O U T
S i pin output
OUT
( i = 3 , 4 )
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 SiC
OUT
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
output goes to the high-impedance state.
Figure 14.39 S
OUT
R e . v 1 1 . 2 M r a 3 . , 0 2 0 0 7
R E J 0 9 B 0 1 0 1 0 - 1 1 2
initial value and how to set it.
OUTi
i i n i t i a l v a l u e
O U T
Port output D
I n i t i a l v a l u e = " H "
S e t t i n g t h e S i Port selection switching
O U T
i n i t i a l v a l u e t o " H " (I/O port S
OUT
( 2 )
i Initial Value Setting
page 221
f o 4 5 8
i Initial Value
OUT
OUTi
( 1 )
D 0
0
( 3 )
i)
output disabled), this
OUTi
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
"H" level is output
from the S
Write to the SiTRR register
Serial transmit/reception starts
14. Serial I/O
i
OUT
i output)
OUT
i pin
OUT