Square-Wave Output Operation; 16-Bit Timer/Event Counter Square-Wave Output Ranges - NEC mPD780208 Subseries User Manual

6.5.5 Square-wave output operation

The 16-bit timer/event counter outputs a square-wave of any frequency with the value preset to the 16-bit compare
register (CR00) as the interval.
The TO0/P30 pin output status is reversed at intervals of the count value preset to CR00 by setting bit 0 (TOE0)
and bit 1 (TOC01) of the 16-bit timer output control register (TOC0) to 1. This enables a square wave with any selected
frequency to be output.
Table 6-6. 16-Bit Timer/Event Counter Square-Wave Output Ranges
TCL06 TCL05 TCL04
0 0 0 2 x TI0 input cycle
0 0 1 2 x 1/f
2
0 1 0 2
3
0 1 1 2
4
1 0 0 2
Remarks 1. f : Main system clock oscillation frequency
X
2. TCL04 to TCL06: Bits 4 to 6 of timer clock select register 0 (TCL0)
3. Figures in parentheses apply to operation with f
Count clock
TM0 count value 0000
Count start
CR00
Note
TO0
Note Initial value of TO0 output can be set by bits 2 and 3 (LVR0 and LVS0) of the 16-bit timer output control
register (TOC0).
142
CHAPTER 6 16-BIT TIMER/EVENT COUNTER
Minimum Pulse Width
(400 ns)
X
x 1/f (800 ns)
X
(1.6 µ s)
x 1/f
X
(3.2 µ s)
x 1/f
X
Figure 6-19. Square-Wave Output Operation Timing
N _ 1
0001 0002
N
User's Manual U11302EJ4V0UM
Maximum Pulse Width
16
2 x TI0 input cycle
16
2 x 1/f (13.1 ms)
X
17
2 x 1/f (26.2 ms)
X
18
2 x 1/f (52.4 ms)
X
19
2 x 1/f (104.9 ms)
X
= 5.0 MHz.
X
N 0000 0001 0002
N
Resolution
TI0 input edge cycle
1/f (200 ns)
X
2 x 1/f (400 ns)
X
2
2 x 1/f (800 ns)
X
(1.6 µ s)
3
2 x 1/f
X
N _ 1
N 0000