M16C Datasheet, PDF (146/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

S I/O3
Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
S I/O3
S I/O3 is exclusive clock-synchronous serial I/O.
Figure 14-1 shows the S I/O3 block diagram, and Figure 14-2 shows the S I/O3 control register.
Table 14-1 shows the specifications of S I/O3.
P90/CLK3
P92/SOUT3
P91/SIN3
f2SIO
f8SIO
f32SIO
SM33
SM36
SM31
SM30
Data bus
Synchronous
circuit
SM36
1/2 1/(n+1)
Transfer rate register (8)
S I/O3 counter (3)
S I/O3
interrupt request
SM32
SM33
SM35 LSB
MSB
S I/O3 transmission/reception register (8)
8
n: A value set in the S I/O3 transfer rate register (01E316)
Figure 14-1. S I/O3 block diagram
S I/O3 control register (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
S3C
Address
01E216
When reset
4016
output,
Bit
symbol
Bit name
SM30 Internal synchronous
clock select bit
SM31
Description
b1 b0
0 0 : Selecting f2SIO
0 1 : Selecting f8SIO
1 0 : Selecting f32SIO
1 1 : Not to be used
RW
SM32 SOUT3 high impedance
control bit
0 : SOUT3 output
1 : SOUT3 high impedance
SM33 S I/O3 port select bit
(Note 2)
0 : Input-output port
1 : SOUT3 output, CLK function
Nothing is assigned.
This bit can neither be set nor read.
When read, the value of this bit is “0”.
SM35 Transfer direction
select bit
0 : LSB first
1 : MSB first
SM36
SM37
Synchronous clock
select bit
SOUT3 initial value
set bit
0 : External clock
1 : Internal clock
Effective when SM33 = 0
0 : L output
1 : H output
Note 1: Set "1" in bit 2 of the protection register (000A16) in advance to write to the
S I/O3 control register.
Note 2: When set "0" to SM33 and select input - output port, set "1" to SM36
and select internal clock, or input "H" to P90 and P95.
Figure 14-2. S I/O3 control register
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