Datasheet

ST72321Rx ST72321ARx ST72321Jx
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ON-CHIP PERIPHERALS (Cont’d)
PWM CONTROL REGISTER (PWMCR)
Read/Write
Reset Value: 0000 0000 (00h)
Bit 7:4 = OE[3:0] PWM Output Enable
These bits are set and cleared by software. They
enable or disable the PWM output channels inde-
pendently acting on the corresponding I/O pin.
0: PWM output disabled.
1: PWM output enabled.
Bit 3:0 = OP[3:0] PWM Output Polarity
These bits are set and cleared by software. They
independently select the polarity of the four PWM
output signals.
Note: When an OPx bit is modified, the PWMx out-
put signal polarity is immediately reversed.
DUTY CYCLE REGISTERS (PWMDCRx)
Read/Write
Reset Value: 0000 0000 (00h)
Bit 7:0 = DC[7:0] Duty Cycle Data
These bits are set and cleared by software.
A PWMDCRx register is associated with the OCRx
register of each PWM channel to determine the
second edge location of the PWM signal (the first
edge location is common to all channels and given
by the ARTARR register). These PWMDCR regis-
ters allow the duty cycle to be set independently
for each PWM channel.
70
OE3 OE2 OE1 OE0 OP3 OP2 OP1 OP0
PWMx output level
OPx
Counter <= OCRx Counter > OCRx
100
011
70
DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0