305
14.3 Control Status Register (PCNH, PCNL)
[bit 12] RTRG: Restart enable bit
This bit enables or disables restart by a software trigger o r trigger input.
[bits 11, 10] CKS1, CKS0: Counter clock select bit
These bits select the counter clock for the 16-bit decrementing c ounter.
φ: Peripheral machine clock
[bit 9] PGMS: PWM output mask selection bit
Setting this bit to "1" can mask the PWM timer so that it out puts only "0" or " 1" regardles s of
the mode, cycle, or duty cycle settings.
To maintain output at a high level in normal polari ty mode o r at a low leve l in i nverse polar ity
mode, write the same value to the cycle setting and duty cycle setting registers, thereb y
inverting the output of the above mask values.
[bit 8]: Reserved
[bits 7, 6] EGS1, SGS0: Trigger input edge select bits
These bits select the edge applicable to the star t sour ce sel ected by general c ontrol registe r
1.
In any edge mode, setting the software trigger bit to "1" enabl es the software trigger.
0 Disable restart (Initial value )
1 Enable restart
Table 14.3-1 Selection of the Coun t Clock
CKS1 CKS0 Cycle
00
φ (Initial value)
01
φ/4
10
φ/16
11
φ/64
Table 14.3-2 PWM Output When "1" is Written to PGMS
Polarity PWM output
Normal polarity Output of L
Inverse polarity Output of H
Table 14.3-3 Selection of Trigger Input Edge
EGS1 EGS0 Edge selec tion
0 0 Invalid (initial value)
0 1 Rising edge
1 0 Falling edge
1 1 Both edges