HT46R064D/065D/066D
Enhanced A/D Type 8-Bit OTP MCU with LED Driver
PWM Output Control
The PWM outputs are pin-shared with the I/O pins PA7 and PC1. To operate as a PWM output and not
as an I/O pin, the correct bits must be set in the CTRL0 register. Azero value must also be written to the
corresponding bit in the I/O port control register PAC.7 and PCC.1 to ensure that the corresponding
PWM output pin is setup as an output. After these two initial steps have been carried out, and of course
after the required PWM value has been written into the PWMn register, writing a high value to the
corresponding bit in the output data register PA.7 and PC.1 will enable the PWM data to appear on the
pin. Writing a zero value will disable the PWM output function and force the output low. In this way,
the Port data output registers can be used as an on/off control for the PWM function. Note that if the
CTRL0 register have selected the PWM function, but a high value has been written to its
corresponding bit in the PAC or PCC control register to configure the pin as an input, then the pin can
still function as a normal input line, with pull-high resistor options.
PWM Programming Example
The following sample program shows how the PWM0 output is setup and controlled.
mov
mov
set
set
clr
set
:
a,64h
pwm0,a
ctrl0.5
ctrl0.3
pac.7
pa.7
; setup PWM value of decimal 100
; select the 7+1 PWM mode
; select pin PA7 to have a PWM function
; setup pin PA7 as an output
; enable the PWM output
:
pa.7
clr
; disable the PWM output_ pin
; PA7 forced low
Rev. 1.00
56
January 12, 2011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
