sh6620a SinoWealth Micro-Electronics Corp. Ltd, sh6620a Datasheet - Page 8

• Manufacturer Part Number: sh6620a
• Description: Mask 4-bit Microcontroller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

4. Timer0
SH6620A has one 8-bit timer. The timer/counter has the following features:
8-bit timer/counter
Readable and writable
Automatic re-loadable counter
8-prescaller scale is available
Internal and external clock select
Interrupt on overflow from $FF to $00
Edge select for external event
Following is a simplified timer block diagram:
4.1. Configuration and Operation
Timer-0 consists of an 8-bit write-only timer load register
(TL0L, TL0H), and an 8-bit read-only timer counter (TC0L,
TC0H). The counter and load register both have LOW order
digits and HIGH order digits. The timer counter can be
initialized by writing data into the timer load register (TL0L,
TL0H). Load register programming: Write the LOW order
digit first and then the HIGH order digit. The timer counter is
loaded with the contents of load register automatically when
the HIGH order digit is written or counter counts overflow
from $FF to $00.
Timer Load Register: Since register H controls the physical
READ and WRITE operation, please follow these rules:
Write Operation:
Low nibble first;
HIGH nibble to update the counter.
T0
Fosc/4
T0E
T0S
System clock
8
Read Operation:
High nibble first;
LOW nibble following.
PRE-SCALER
T0M
Load Reg. L
Latch Reg. L
T0C
8-bit timer counter
8-BIT COUNTER
Load Reg. H
SH6620A