NEC UPD789026 Series, User Manual

Page: 106 / 213

CHAPTER 7 8-BIT TIMER/EVENT COUNTER
User's Manual U11919EJ3V0UM00
106
7.2 8-Bit Timer/Event Counter Configuration
The 8-bit timer/event counter consists of the following hardware configuration.
Table 7-3. Configuration of 8-Bit Timer/Event Counter 00
Item Configuration
Timer counter 8 bits
×
1 (TM00)
Register Compare register: 8 bits
×
1 (CR00)
Timer output 1 (TO0)
Control register 8-bit timer mode control register 00 (TMC00)
Port mode register 5 (PM5)
Figure 7-1. Block Diagram of 8-Bit Timer/Event Counter 00
Internal Bus
8-Bit Compare Register 00
(CR00)
Match
TO0/P50/TI0
INTTM0
f
X
f
X
/2
5
TI0/P50/TO0
Selector
Clear
8-Bit Timer Counter 00
(TM00)
2
Internal Bus
TCE00 TCL001 TCL000 TOE00
8-Bit Timer Mode Control Register 1
F/F
P50
Output Latch
PM50
Selector
(1) 8-bit compare register 00 (CR00)
This is an 8-bit register to compare the value set to CR00 with the 8-bit timer register 00 (TM00) count
value, and if they match, generates an interrupt request (INTTM0).
CR00 is set with an 8-bit memory manipulation instruction. The 00H to FFH values can be set.
RESET input makes CR00 undefined.
Caution Before rewriting CR00, stop the timer operation. If CR00 is rewritten while the timer
operation is enabled, the coincidence interrupt request signal may be generated
immediately.
(2) 8-bit timer counter 00 (TM00)
This is an 8-bit register to count pulses.
TM00 is read with an 8-bit memory manipulation instruction.
RESET input clears TM00 to 00H.
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