NEC UPD789026 Series, User Manual

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CHAPTER 7 8-BIT TIMER/EVENT COUNTER
User's Manual U11919EJ3V0UM00
107
7.3 8-Bit Timer/Event Counter Control Registers
The following two types of registers are used to control the 8-bit timer/event counter.
• 8-bit timer mode control register 00 (TMC00)
• Port mode register 5 (PM5)
(1) 8-bit timer mode control register 00 (TMC00)
TMC00 determines whether to enable or disable 8-bit timer counter 00 (TM00), specifies the count clock for
TM00, and controls the operation of the output control circuit of 8-bit timer/event counter 00.
TMC00 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears TMC00 to 00H.
Figure 7-2. 8-Bit Timer Mode Control Register 00 Format
TCE00 0 0 0 0 TCL001 TCL000 TOE00 TMC00
Symbol Address After Reset R/W
FF53H 00H R/W
6 <7> 5 4 3 2 1 <0>
TCL001
0
0
1
1
8-Bit Timer Counter 00 Count Clock Selection TCL000
0
1
0
1
f
X
f
X
/2
5
Rising edge of TI0
Note
Falling edge of TI0
Note
TCE00
0
1
8-Bit Timer Counter 00 Operation Control
Operation disabled (TM00 is cleared to 0.)
Operation enabled
(5.0 MHz)
(156 kHz)
TOE00
0
1
8-Bit Timer/Event Counter 00 Output Control
Output disabled (port mode)
Output enabled
Note When inputting a clock signal eternally, timer output cannot be used.
Caution Always stop the timer before setting TMC00.
Remarks 1. f
X
: System clock oscillation frequency
2. The parenthesized values apply to operation at f
X
= 5.0 MHz.
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