Hitachi AP1 - Page 316

HMCS404AC-------------------------------------------------- __________________ _
Table 7. Serial Mode Register
SMR
Bit 3
o
Used as R40 port input/output pin
Used
as SOl< input/output pin
SMR
Transfer Clock
Presealer
System Clock
Bit 2
Bit 1
Bit 0
R4o/SCK Port Clock Source
Divide
Divide
Ratio
Ratio
0
0
0
SCI{
Presealer
+2048
+4096
Output
0 0
1
SCK
Presealer
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
Seriel
Output Data
Serial
Input Data
LatCh Timing
I I I I I I I I
Fig.10 Serial Interface I/O Timing Chart
• SERIAL Interrupt Requllt Fleg (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 Malk (lMS: $003, 1)
The SERIAL Interrupt Mask masks the interrupt request.
Table 8. SERIAL Interrupt Request Flag
SERIAL Interrupt Request Flag
I nterrupt Request
o
No
Yes
314
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