HT82K74EE HOLTEK [Holtek Semiconductor Inc], HT82K74EE Datasheet - Page 33

• Manufacturer Part Number: HT82K74EE
• Description: 27MHz Keyboard/ Mouse TX 8-Bit MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

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 1 .
Rev. 1.00
0~1
2
3
4
5~7
Bit No.
Bit No.
0~7
CLK_DIV
CAP_EN
OSC_MOD
I_SEL
Reserved bit
Fun. Name
Period Timer
Function
Name
R/W
R/W
R/W
R/W
R/W
R/W
27MHz Oscillator Control Register - RFCTR (21H)
R/W
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)
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.
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.
27MHz oscillator (OSC) current control when OSC operates in frequency modu-
lation mode.
0: normal current state is selected when the V
than 3V.
1: high current state is selected when the V
Always read 0
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:
Period Timer Register - PTR
I/O Port wake-up
INT wake-up
Reset
The Period Timer is reached to the values specified by the PTR.
33
Description for mouse mode
Description
HT82K74E/HT82K74EE
DD
DD
voltage is lower than 3V.
voltage is equal to or higher
December 15, 2009