HT82K74E datasheet(33/56 Pages) HOLTEK

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HT82K74E/HT82K74EE

Rev. 1.00

December 15, 2009

Bit No.

Fun. Name

R/W

Description for mouse mode

0~1

CLK_DIV

R/W

MCU system clock division selection

00: system clock= system oscillator output clock/4 (6.75MHz)

01: system clock= system oscillator output clock/8 (3.3MHz)

10: system clock= system oscillator output clock/16 (1.68MHz)

11: system clock= system oscillator output clock/1 (only for 4MHz)

CAP_EN

R/W

27MHz oscillator built-in capacitor enable control

0: disable the built-in capacitor connection to both OSC1 and OSC2 (default)

1: enable the built-in capacitor connection to both OSC1 and OSC2 where the

built-in capacitors for both OSC1 and OSC2 are defined by the OSC CAP con-

trol register OSCC.

OSC_MOD

R/W

27MHz oscillator (OSC) operating mode control

0: OSC operates in normal mode without frequency modulation.

1: OSC operates in frequency modulation mode for RF transmission.

I_SEL

R/W

27MHz oscillator (OSC) current control when OSC operates in frequency modu-

lation mode.

0: normal current state is selected when the VDD voltage is equal to or higher

than 3V.

1: high current state is selected when the VDD voltage is lower than 3V.

5~7

Reserved bit

R/W

Always read 0

27MHz Oscillator Control Register

- RFCTR (21H)

Period Timer Register

- PTR

This register is used to define the period of the timer which always counts in the Power Down Mode. Once the timer is

reached, the MCU will be woken-up by Period Timer Register overflow. Once the MCU is woken-up by the period timer,

the CNT_WK bit of the wake-up Register is set to

²1².

Bit No.

Function

Name

R/W

Description

0~7

Period Timer

R/W

The Period Timer is the time interval generator with one second as a unit. If

the bits [7:0] are equal to 00H, the MCU will be woken up by one of the

wake-up source mentioned in Wake-up Section except the PTR overflow

event. If the bits [7:0] are not equal to 00H, the MCU will be woken up from

the Power Down mode by the following events except WDT overflow event:

· I/O Port wake-up

· INT wake-up

· Reset

· The Period Timer is reached to the values specified by the PTR.

Period Timer Register

- PTR

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