HT82J97E datasheet(21/46 Pages) HOLTEK

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HT82J97E

Rev. 1.30

May 10, 2004

To Configure PWM Block

The HT82J97E has two PWM outputs (PWM1 and

PWM2), which are shared with PC2, PC3 and can be

easily enabled or disabled by the PWM1_EN or

PWM2_EN bit of PORT_PC (16H) respectively.

Also there is a one 8-bit PWMBR (PWM Base Period

form cycle period.

PWM cycle period = 256

´1/fSYS´(PWMBR+1), or

256

´4/fSYS´(PWMBR+1)

where 1/fSYS or 4/fSYS is defined by PWM_S bit of the

PORT_PC (16H)

For example if PWMBR = 17, 4/fSYS (T1) is selected and

fSYS = 6MHz.

So both output waveform cycle period is 256

´4/6

´(17+1) = about 3072ms (0.325kHz)

Now user can easily define the corresponding PWM

duty by configuring the PWM1DR (for PWM1) or

PWM2DR (for PWM2) duty registers

PWM1 duty (high pulse) = (PWM1DR+1)/256

´100%

PWM1 high pulse period = PWM1 duty

´PWM cycle pe-

riod

PWM1 Low pulse period = PWM cycle period-high pulse

period

PWM2 duty (high pulse) = (PWM2DR+1)/256

´100%

PWM2 high pulse period = PWM2 duty

´PWM cycle pe-

riod

PWM2 Low pulse period = PWM cycle period-high pulse

period

For example PWMBR=17, PWM1DR=63, 4/fSYS (T1) is

selected and fSYS=6MHz

PWM cycle period = 256

´4/6´(17+1) = about 3072ms

(0.325kHz)

PWM1 duty = (63+1)/256 = 25%

PWM1 high pulse period = 25%

´3072ms = 768ms

PWM1 low pulse period = 3072

ms -768ms = 2304ms

P W M H i g h P u l s e

P W M C y c l e P e r i o d

I/O Port Special Registers Definition

· Port-A (12H)

- PA

Bits

Labels

Read/Write

Option

Functions

(12H)

PA0

R/W

I/O (R/W) has pull-low and pull-high ROM code option.

Has falling edge wake-up ROM code option.

PA1

R/W

I/O (R/W) has pull-low and pull-high option.

Has falling edge wake-up option.

PA2

R/W

I/O (R/W) has pull-low and pull-high option.

Has falling edge and rising edge wake-up option.

PA3

R/W

I/O (R/W) has pull-low and pull-high option.

Has falling edge and rising edge wake-up option.

PA4

R/W

I/O (R/W) has pull-high option.

Has falling edge wake-up option.

PA5

R/W

I/O (R/W) has pull-high option.

Has falling edge wake-up option.

PA6

R/W

I/O (R/W) has pull-high option.

Has falling edge wake-up option.

PA7

R/W

I/O (R/W) has pull-high option.

Has falling edge wake-up option, pin-shared with timer in-

put pin.

· Port-A Control (13H) - PAC

This port configure the input or output mode of Port-A

HT82J97E Datasheet(PDF) 21 Page - Holtek Semiconductor Inc

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