NEC PD78212, User Manual

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262
µ
PD78214 Sub-Series
10.3 CONTROL REGISTERS
10.3.1 Clock Synchronous Serial Interface Mode Register (CSIM)
This 8-bit register specifies a serial interface operation mode, serial clock and wake-up function.
The 8-bit manipulation instruction and bit manipulation instruction can read and write the contents of the CSIM
register. Fig. 10-2 shows the format.
The register is set to 00H when RESET is input.
Fig. 10-2 Format of the Clock Synchronous Serial Interface Mode Register (CSIM)
CTXE
7
CRXE
6
WUP
5
0
Note 1
4
MOD1
3
0
Note 1
2
CLS1
1
CLS0
0
CSIM
CLS1
Internal
clock
External clock
Selects serial clock
0
0
CLS0
0
1
SCK pin
Master/slave selection in
SBI mode
8-bit timer/counter 3
output/2
Input
1 0
1 1
f
CLK
/32
Note 2
f
CLK
/8
Note 2
Output
Slave
Master
WUP
3-wire serial I/O mode
Operation mode
0
0
MOD1
0
1
Controls wakeup function
SBI mode
1 1
Generates interrupt request at
each serial transfer
Generates interrupt request only
when address is received
CRXE
Disabled
Reception
0
1
Enabled
CTXE
Disabled
Transmission
0
1
Enabled
Notes 1. Always write 0 into bits 2 and 4.
2. f
CLK
: Internal system clock
Caution Do not change CTXE from 0 to 1 and CRXE from 1 to 0, or vice versa, by means of a single instruction. If this is attempted, the serial
clock counter will malfunction and the first communication after the change will be terminated before the eighth bit is sent. To
change these statuses, use two instructions, as shown below:
Example Changing CTXE from 1 to 0 and CRXE from 0 to 1
CLR1 CTXE
SET1 CRXE