HT82J97E
Rev. 1.30
21
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
Register, 18H) which defines both PWM output wave-
form cycle period.
PWM cycle period = 256 1/f
SYS
(PWMBR+1), or
256 4/f
SYS
(PWMBR+1)
where 1/f
SYS
or 4/f
SYS
is defined by PWM_S bit of the
PORT_PC (16H)
For example if PWMBR = 17, 4/f
SYS
(T1) is selected and
f
SYS
= 6MHz.
So both output waveform cycle period is 256 4/6
(17+1) = about 3072 s (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
PWM1Lowpulseperiod=PWMcycleperiod-highpulse
period
PWM2 duty (high pulse) = (PWM2DR+1)/256 100%
PWM2 high pulse period = PWM2 duty PWM cycle pe-
riod
PWM2Lowpulseperiod=PWMcycleperiod-highpulse
period
For example PWMBR=17, PWM1DR=63, 4/f
SYS
(T1) is
selected and f
SYS
=6MHz
PWM cycle period = 256 4/6 (17+1) = about 3072 s
(0.325kHz)
PWM1 duty = (63+1)/256 = 25%
PWM1 high pulse period = 25% 3072 s = 768 s
PWM1 low pulse period = 3072 s -768 s = 2304 s
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I/O Port Special Registers Definition
Port-A (12H)
PA
Register
Bits
Labels
Read/Write
Option
Functions
PA
(12H)
0
PA0
R/W
I/O (R/W) has pull-low and pull-high ROM code option.
Has falling edge wake-up ROM code option.
1
PA1
R/W
I/O (R/W) has pull-low and pull-high option.
Has falling edge wake-up option.
2
PA2
R/W
I/O (R/W) has pull-low and pull-high option.
Has falling edge and rising edge wake-up option.
3
PA3
R/W
I/O (R/W) has pull-low and pull-high option.
Has falling edge and rising edge wake-up option.
4
PA4
R/W
I/O (R/W) has pull-high option.
Has falling edge wake-up option.
5
PA5
R/W
I/O (R/W) has pull-high option.
Has falling edge wake-up option.
6
PA6
R/W
I/O (R/W) has pull-high option.
Has falling edge wake-up option.
7
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)
This port configure the input or output mode of Port-A
PAC