Hitachi AP1 Data Book page 354

HMCS404CL------------------------------------------------------------------------
Table 7. Serial Mode Register
SMR
Bit 3
o
Used as R40 port input/output pin
Used as SCK input/output pin
SMR
Transfer Clock
Prescaler
System Clock
Bit 2 Bit 1 Bit 0
R4o/SCK Port Clock Source Divide Divide
Ratio Ratio
0 0
0
SCK
Prescaler
+ 2048 +4096
Output
0 0 1
SCK
Prescaler
512 + 1024
Output
0 1 0
SCK
Prescaler
128 256
Output
0
1
1
SCK
Prescaler 32 64
Output
1
0 0
SCK
Prescaler
8 16
Output
1
0
1
SCK
Prescaler 2 4
Output
1
1 0
SCK System
-
1
Output Clock
1
1 1
SCK External
- -
Input
Clock
Transfer Clock
Serial Output Data
Serial Input Data
Latch Timing
I I II I I I· I
Fig. 10 Serial Interface I/O Timing Chart
• SERIAL Interrupt Request Flag (lFS: $003, 0)
The SERIAL Interrupt Request Flag will be set after the
eight transfer clock signals or transmit/receive discontinued
operation by resetting the Octal Counter.
• SERIAL Interrupt Mask (lMS: $003, 1)
The SERIAL Interrupt Mask masks the interrupt request.
Table 8. SERIAL Interrupt Request Flag
SERIAL Interrupt Request Flag Interrupt Request
o
No
Yes
352
Table 9. SERIAL Interrupt Mask
SERIAL Interrupt Mask Interrupt Request
o
Enable
Disable (mask)
• Selection of the Operation Mode
Table 10 shows the operation mode of the serial interface.
Select a combination of the value in the Port Mode Register and
the Serial Mode Register according to Table 10.
Initialize the serial interface by the Write Signal to the
Serial Mode Register, when the Operation Mode is changed.
• Operating State of Serial Interface
The serial interface has 3 operating states as shown in Fig. 11.
The serial interface gets into "STS waiting state" by 2 ways:
one way is to change the operation mode by changing the data