HT46R006 datasheet(45/72 Pages) HOLTEK

45 / 72 page

HT48R006/HT46R006

Rev. 1.00

October 24, 2011

PWM Output Control

The PWM output is pin-shared with the I/O pin PA2. To

operate as a PWM output and not as an I/O pin, the cor-

rect bits must be set in the CTRL0 register. A zero value

must also be written to the corresponding bit in the I/O

port control register PAC.2 to ensure that the corre-

sponding 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 corre-

sponding bit in the output data register PA.2 will enable

the PWM data to appear on the pin. Writing a zero value

will disable the PWM output function and force the out-

put 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 func-

tion, but a high value has been written to its correspond-

ing bit in the PAC 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 a,64h

; setup PWM value of decimal 100

mov pwm0,a

set ctrl0.5

; select the 7+1 PWM mode

set ctrl0.2

; select pin PA2 to have a PWM function

clr pac.2

; setup pin PA2 as an output

set pa.2

; enable the PWM output

clr pa.2

; disable the PWM output_ pin

; PA2 forced low

HT46R006 датащи(PDF) 45 Page - Holtek Semiconductor Inc