UPSD33XX Datasheet, PDF (128/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

uPSD33xx
PWM Mode - (X8), Programmable Frequency
In this mode, the PWM frequency is not deter-
mined by the overflow of the low byte of the
Counter. Instead, the frequency is determined by
the PWMFm Register. The user can load a value
in the PWMFm Register, which is then compared
to the low byte of the Counter. If there is a match,
the Counter is cleared and the Load registers
(PWMFm, CAPCOMHn) are re-loaded for the next
PWM pulse. There is only one PWMFm Register
which serves all 3 TCM in a PCA block.
If one of the TCM modules is operating in this
mode, the other modules in the PCA must be con-
figured to the same mode or left not to be used.
The duty cycle of the PWM can be specified in the
CAPCOMHn Register as in the PWM with fixed
frequency mode. Different TCM modules can have
their own duty cycle.
Note: The value in the Frequency Register (PWM-
Fm) must be larger than the duty cycle register
(CAPCOM).
Figure 50. PWM Mode - (X8) Programmable Frequency
PWM FREQ COMPARE
PWMFm
8
PWMFm = PCACLm
CAPCOMHn
8
PCACHm
CAPCOMLn
ENABLE
8-bit COMPARATORm
ENABLE
MATCH SET
8-bit COMPARATORn
S
Q
8
PCACLm
CLR
R
Q
CLR
CEXn
TCMMODEn EINTF E_COMP CAP_PE CAP_NE MATCH TOGGLE PWM1
0
0
0
0
0
PWM0
Note: m = 0: n = 0, 1, or 2
m = 1: n = 3, 4, or 5
128/231
AI07860