150
CHAPTER 11 SERIAL INTERFACES SIO30 TO SIO32
User’s Manual U15104EJ2V0UD
11.3 Registers Controlling Serial Interfaces SIO30 to SIO32
The following registers control the serial interface SIO3n.
• Serial operating mode registers 30 to 32 (CSIM30 to CSIM32)
• Serial port select register 32 (SIO32SEL)
(1) Serial operating mode register 30 to 32 (CSIM30 to CSIM32)
These registers select the serial clock of SIO3n and an operating mode, and enable or disable the operation.
CSIM3n is set with a 1-bit or 8-bit memory manipulation instruction.
Reset input clears these registers to 00H.
Figure 11-4. Format of Serial Operating Mode Registers 30 to 32 (CSIM30 to CSIM32)
CSIE3n
Enable/disable of SIO3n operation
Shift register operation
Serial counter
Port
0
Disables operation
Cleared
Port function
Note 1
1
Enables operation
Enables counter operation
Serial fu port function
Note 2
MODE3n
Transfer operation mode flag
Operating mode
Transfer start trigger
SO3n output
0
Transmit or transmit/receive mode
SIO3n write
Serial output
1
Receive only mode
SIO3n read
Fixed to low level
Note 3
SCL3n1 SCL3n0
Clock selection
0
0
External clock input to SCK3n
0
1
f
X
/2
4
(281 kHz)
1
0
f
X
/2
5
(141 kHz)
1
1
f
X
/2
6
(70.3 kHz)
Notes 1. The SI3n, SO3n, and SCK3n pins can be used as port pins when CSIE3n = 0 (when SIO3n operation
is stopped).
2. When CSIE3n = 1 (when SIO3n operation is enabled), the SI3n pin can be used as a port pin if
only the transmission function is used, and the SO3n pin can be used as a port pin in the receive
mode.
3. The SO3n pin can be used as a port pin.
Remarks 1. f
X
: System clock oscillation frequency
2. ( ): f
X
= 4.5 MHz
<7>
6
5
4
3
CSIE30
0
0
0
0
2
MODE30
1
SCL301
0
SCL300
Symbol
CSIM30
R/W
R/W
After reset
00H
Address
FF6FH
<7>
6
5
4
3
CSIE31
0
0
0
0
2
MODE31
1
SCL311
0
SCL310
CSIM31
R/W
00H
FF6DH
<7>
6
5
4
3
CSIE32
0
0
0
0
2
MODE32
1
SCL321
0
SCL320
CSIM32
R/W
00H
FF6BH
Содержание mPD178053
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