sh66k33a SinoWealth Micro-Electronics Corp. Ltd, sh66k33a Datasheet - Page 9

• Manufacturer Part Number: sh66k33a
• Description: Mask 1k 4-bit Micro-controller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

7. Timer0
The timer/counter has the following features:
The following is a simplified timer block diagram.
The timers provide the following functions:
7.1. Timer0 Configuration and Operation
The Timer0 consist of an 8-bit write-only timer load register
(TL0L, TL0H) and an 8-bit read-only timer counter (TC0L,
TC0H). Each of them has low order digits and high order
digits. Writing data into the timer load register (TL0L, TL0H)
can initialize the timer counter.
7.2. Timer Mode Register
The timer can be programmed in several different prescalers by setting Timer Mode register (TM0).
The 8-bit counter prescaler overflow output pulses. The Timer Mode registers (TM0) are 3-bit registers used for the timer
control as shown in Table 1. These mode registers select the input pulse sources into the timer.
Table 1. Timer0 Mode Register ($02)
- 8-bit up-counting timer/counter.
- Automatic re-load counter.
- 8-level prescaler.
- Interrupt on overflow from $FF to $00.
- Programmable interval timer function.
- Read counter value.
System
clock
TM0.2
0
0
0
0
1
1
1
1
TM.2
Prescaler
TM0.1
t
TM.1
osc
0
0
1
1
0
0
1
1
TM.0
SYNC
TM0.0
0
1
0
1
0
1
0
1
COUNTER
8-BIT
Prescaler Divide Ratio
/2
/2
/2
/2
/2
/2
/2
/2
11
9
7
5
3
2
1
0
9
The low-order digit should be written first, and then the
high-order digit. The timer counter is automatically loaded
with the contents of the load register when the high order
digit is written or counter counts overflow from $FF to $00.
Timer Load Register: Since the register H controls the
physical READ and WRITE operations.
Please follow these steps:
Write Operation:
Read Operation:
Low nibble first
High nibble to update the counter
High nibble first
Low nibble followed.
Load Reg. L
Latch Reg. L
Clock Source
System clock
System clock
System clock
System clock
System clock
System clock
System clock
System clock
8-bit timer counter
Load Reg. H
SH66K33A