HT56R656 datasheet(27/108 Pages) HOLTEK

27 / 108 page

HT56R62/HT56R65

HT56R642/HT56R644/HT56R654/HT56R656

Rev. 1.00

July 20, 2009

A/D Converter Registers

ADRL, ADRH, ADCR, ACSR

The device contains a multiple channel 12-bit A/D con-

verter. The correct operation of the A/D requires the use

of two data registers and two control registers. The two

data registers, a high byte data register known as

ADRH, and a low byte data register known as ADRL, are

the register locations where the digital value is placed

after the completion of an analog to digital conversion

cycle. Functions such as the A/D enable/disable, A/D

channel selection and A/D clock frequency are deter-

mined using the two control registers, ADCR and ACSR.

Serial Interface Registers

The device contains two serial interfaces, an SPI and an

2C interface. The SIMCTL0, SIMCTL1, SIMCTL2 and

SIMAR are the control registers for the Serial Interface

function while the SIMDR is the data register for the Se-

rial Interface Data.

Port A Wake-up Register

- PAWU

All pins on Port A have a wake-up function enable a low

going edge on these pins to wake-up the device when it

is in a power down mode. The pins on Port A that are

used to have a wake-up function are selected using this

resister.

Pull-High Resistors

- PAPU, PBPU, PDPU

All I/O pins on Ports PA, PB and PD, if setup as inputs,

can be connected to an internal pull-high resistor. The

pins which require a pull-high resistor to be connected

are selected using these registers.

- CLKMOD

The device operates using a dual clock system whose

mode is controlled using this register. The register con-

trols functions such as the clock source, the idle mode

enable and the division ratio for the slow clock.

LCD/LED Registers

LCDCTRL, LEDCTRL, LCDOUT1, LCDOUT2

The device contains a fully integrated LCD/LED Driver

function which can be setup in various configurations al-

lowing it to control a wide range of external LCD and

LED panels. Most of these options are controlled using

the LCDCTRL and LECTRL registers. As some of the

LCD segment driving pins can also be setup to be used

as CMOS outputs, two registers, LCDOUT1 and

LCDOUT2, are used to select the required function.

Miscellaneous Register

- MISC

The miscellaneous register is used to control two func-

tions. The four lower bits are used for the Watchdog

Timer control, while the highest four bits are used to se-

lect open drain outputs for pins PA0~PA3.

Input/Output Ports

Holtek microcontrollers offer considerable flexibility on

their I/O ports. With the input or output designation of ev-

ery pin fully under user program control, pull-high selec-

tions for all ports and wake-up selections on certain

pins, the user is provided with an I/O structure to meet

the needs of a wide range of application possibilities.

The device provides 24 bidirectional input/output lines

labeled with port names PA, PB and PD. These I/O ports

are mapped to the RAM Data Memory with specific ad-

dresses as shown in the Special Purpose Data Memory

table. All of these I/O ports can be used for input and

output operations. For input operation, these ports are

non-latching, which means the inputs must be ready at

the T2 rising edge of instruction

²MOV A,[m]², where m

denotes the port address. For output operation, all the

data is latched and remains unchanged until the output

latch is rewritten.

Pull-high Resistors

Many product applications require pull-high resistors for

their switch inputs usually requiring the use of an exter-

nal resistor. To eliminate the need for these external re-

sistors, all I/O pins, when configured as an input have

the capability of being connected to an internal pull-high

resistor. These pull-high resistors are selected using

registers PAPU, PBPU and PDPU and are implemented

using weak PMOS transistors.

Port A Wake-up

The HALT instruction forces the microcontroller into a

Power Down condition which preserves power, a fea-

ture that is important for battery and other low-power ap-

plications. Various methods exist to wake-up the

microcontroller, one of which is to change the logic

condition on one of the Port A pins from high to low. After

a HALT instruction forces the microcontroller into enter-

ing a Power Down condition, the processor will remain

in a low-power state until the logic condition of the se-

lected wake-up pin on Port A changes from high to low.

This function is especially suitable for applications that

can be woken up via external switches. Each pin on Port

A can be selected individually to have this wake-up fea-

ture using the PAWU register.

Port A Open Drain Function

All I/O pins in the device have CMOS structures, how-

ever Port A pins PA0~PA3 can also be setup as open

drain structures. This is implemented using the ODE0~

ODE3 bits in the MISC register.

HT56R656 数据表(PDF) 27 Page - Holtek Semiconductor Inc

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