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M16C/62P Group (M16C/62P, M16C/62PT)
Table 17.20 SI/O3 and SI/O4 Specifications
Item
Transfer Data Format
Transfer Clock
Transmission/Reception
Start Condition
Interrupt Request
Generation Timing
CLKi Pin Function
SOUTi Pin Function
SINi Pin Function
Select Function
NOTES:
1. To set SMi6 bit to "0" (external clock), follow the procedure described below.
• If the SMi4 bit = 0, write transmit data to the SiTRR register while input on the CLKi pin is high. The same
applies when rewriting the SMi7 bit in the SiC register.
• If the SMi4 bit = 1, write transmit data to the SiTRR register while input on the CLKi pin is low. The same applies
when rewriting the SMi7 bit.
• Because shift operation continues as long as the transfer clock is supplied to the SI/Oi circuit, stop the transfer
clock after supplying eight pulses. If the SMi6 bit = 1 (internal clock), the transfer clock automatically stops.
2. Unlike UART0 to UART2, SI/Oi (i = 3 to 4) is not separated between the transfer register and buffer. Therefore,
do not write the next transmit data to the SiTRR register during transmission.
3. When SMi6 bit = 1 (internal clock), SOUTi retains the last data for a 1/2 transfer clock period after completion of
transfer and, thereafter, goes to a high-impedance state. However, if transmit data is written to the SiTRR
register during this period, SOUTi immediately goes to a high-impedance state, with the data hold time thereby
reduced.
4. When the SMi6 bit = 1 (internal clock), the transfer clock stops in the high state if the SMi4 bit = 0, or stops in the
low state if the SMi4 bit = 1.
R
e
. v
2
3 .
0
S
e
p
0
, 1
2
0
0
4
R
E
J
0
9
B
0
1
8
5
0 -
2
3
0
Z
• Transfer data length: 8 bits
• SMi6 bit in SiC (i=3, 4) register = 1 (internal clock) : fj/ 2(n+1)
fj = f1SIO, f8SIO, f32SIO. n=Setting value of SiBRG register
• SMi6 bit = 0 (external clock) : Input from CLKi pin
• Before transmission/reception can start, the following requirements must be met
Write transmit data to the SiTRR register
• When SMi4 bit in SiC register = 0
The rising edge of the last transfer clock pulse
• When SMi4 = 1
The falling edge of the last transfer clock pulse
I/O port, transfer clock input, transfer clock output
I/O port, transmit data output, high-impedance
I/O port, receive data input
• LSB first or MSB first selection
Whether to start sending/receiving data beginning with bit 0 or beginning with bit 7
can be selected
• Function for setting an SOUTi initial value set function
When the SMi6 bit in the SiC register = 0 (external clock), the SOUTi pin output level
while not transmitting can be selected.
• CLK polarity selection
Whether transmit data is output/input timing at the rising edge or falling edge of
transfer clock can be selected.
page 204
f o
3
6
4
Specification
(1)
(2, 3)
(4)
(4)
17. Serial I/O
00h to FFh.
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