NEC switch - 6.3 Registers Controlling 8-Bit Timer;Event Counters 00 and 01

CHAPTER 6 8-BIT TIMER/EVENT COUNTERS 00 AND 01
User’s Manual U12978EJ3V0UD
82
6.3 Registers Controlling 8-Bit Timer/Event Counters 00 and 01
The following two types of registers are used to control 8-bit timer/event counters 00 and 01.
• 8-bit timer mode control registers 00 and 01 (TMC00 and TMC01)
• Port mode register 2 (PM2)
(1) 8-bit timer mode control register 00 (TMC00)
This register enables/stops operation of 8-bit timer counter 00 (TM00) and sets the counter clock of 8-bit timer
00.
TMC00 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets TMC00 to 00H.
Figure 6-3. Format of 8-Bit Timer Mode Control Register 00
TCE00 00000 TCL000 0TMC00
R/W
FF53H 00H R/W
654321
TCL000
0
0
TCE00
0
1
<7> 0
Operation enabled
Symbol
Address After reset
8-bit timer 00 count clock selection
8-bit timer counter 00 operation control
Operation disabled (TM00 cleared to 0)
fX/2
6
(93.8 kHz)
f
X/2
9
(11.7 kHz)
Caution Be sure to set the count clock after the timer operation is stopped (TCE00 = 0).
Refer to 6.4 Operation of 8-Bit Timer/Event Counters 00 and 01 for details.
Remarks 1. fX
: System clock oscillation frequency
2. The parenthesized values apply to operation at f
X
= 6.0 MHz.