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Rev.2.00 Nov 28, 2005 page 201 of 378
REJ09B0124-0200
M16C/6N Group (M16C/6NK, M16C/6NM) 15. Serial Interface
Under development
This document is under development and its contents are subject to change.
15.2.3 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
(1)
.
Figure 15.41 shows the timing chart for setting an SOUTi initial value and how to set it.
NOTE:
1. When CAN0 function is selected, P7_4, P7_5 and P8_0 can be used as input/output pins for SI/O4.
When CAN0 function is not selected, P9_5, P9_6 and P9_7 can be used as input/output pis for SI/O4.
Figure 15.41 SOUTi’s Initial Value Setting
Setting the SOUTi
initial value to "H"
(2)
Port selection switching
(I/O port SOUTi)
D0
Initial value = H
(1)
Port output
D0
Signal written to
SiTRR register
SOUTi (internal)
SMi7 bit
SOUTi output
SMi3 bit
(Example) When "H" selected for SOUTi initial value
i = 3 to 6 (5 and 6 are only in the 128-pin version.)
* 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)
SMi6 = 0 (external clock)
NOTES:
1.If the SMi6 bit = 1 (internal clock) or if the SMi2 bit = 1 (SOUTi output disabled), this output
goes to the high-impedance state.
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).
"H" level is output
from the SOUTi pin
Serial transmit/reception starts
Setting of the initial value of SOUTi
output and starting of
transmission/reception
Set the SMi3 bit to "1"
(SOUTi pin functions as SOUTi output)
Write to the SiTRR register
Set the SMi3 bit to "0"
(SOUTi pin functions as an I/O port)
Set the SMi7 bit to "1"
(SOUTi initial value = H)