HT48R02B datasheet(18/71 Pages) HOLTEK

18 / 71 page

HT46R01B/02B/01N/02N

HT48R01B/02B/01N/02N

Rev.1.00

December 15, 2009

Input/Output Ports and Control Registers

Within the area of Special Function Registers, the port

PA, PB, etc data I/O registers and their associated con-

trol register PAC, PBC, etc play a prominent role. These

registers are mapped to specific addresses within the

Data Memory as shown in the Data Memory table. The

data I/O registers, are used to transfer the appropriate

output or input data on the port. The control registers

specifies which pins of the port are set as inputs and

which are set as outputs. To setup a pin as an input, the

corresponding bit of the control register must be set

high, for an output it must be set low. During program in-

itialisation, it is important to first setup the control regis-

ters to specify which pins are outputs and which are

inputs before reading data from or writing data to the I/O

ports. One flexible feature of these registers is the ability

to directly program single bits using the

²SET [m].i² and

²CLR [m].i² instructions. The ability to change I/O pins

from output to input and vice versa by manipulating spe-

cific bits of the I/O control registers during normal pro-

gram operation is a useful feature of these devices.

System Control Registers

- CTRL0, CTRL1

These registers are used to provide control over various

internal functions. Some of these include the PFD con-

trol, PWM control, certain system clock options, the LXT

Oscillator low power control, external Interrupt edge trig-

ger type, Watchdog Timer enable function, Time Base

function division ratio, and the LXT oscillator enable

control.

Wake-up Function Register

- PAWK

When the microcontroller enters the Sleep Mode, vari-

ous methods exist to wake the device up and continue

with normal operation. One method is to allow a falling

edge on the I/O pins to have a wake-up function. This

to have this wake-up function.

Pull-high Registers

- PAPU, PBPU

The I/O pins, if configured as inputs, can have internal

pull-high resistors connected, which eliminates the need

for external pull-high resistors. This register selects which

I/O pins are connected to internal pull-high resistors.

· CTRL0 Register - HT46R01B/HT46R02B/HT46R01N/HT46R02N

Bit

76543210

Name

PFDCS

PWMSEL

PWMC0

PFDC

LXTLP

CLKMOD

R/W

POR

0000

Bit 7

unimplemented, read as

²0²

Bit 6

PFDCS: PFD clock source

0: timer0

1: timer1

Bit 5

PWMSEL: PWM type selection

0: 6+2

1: 7+1

Bit 4

unimplemented, read as

²0²

Bit 3

PWMC0: I/O or PWM

0: I/O

1: PWM

Bit 2

PFDC: I/O or PFD

0: I/O

1: PFD

Bit 1

LXTLP: LXT oscillator low power control function

0: LXT Oscillator quick start-up mode

1: LXT Oscillator Low Power Mode

Bit 0

CLKMOD: system clock mode selection.

0: High speed - HIRC used as system clock

1: Low speed - LXT used as system clock, HIRC oscillator stopped.

These selections are only valid if the oscillator configuration options

have selected the HIRC+LXT.

Note:

If PWM output is selected by PWMC0 bit, fTP comes always from fSYS.

(fTP is the clock source for timer0/2, time base and PWM)

HT48R02B Datasheet(PDF) 18 Page - Holtek Semiconductor Inc

HT48R02B Datasheet(HTML) 18 Page - Holtek Semiconductor Inc

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