HT67F60 datasheet(64/242 Pages) HOLTEK

64 / 242 page

Rev. 1.50

March 06 , 2012

Rev. 1.50

March 06 , 2012

HT67F30/HT67F40/HT67F50/HT67F60

TinyPowerTM A/D Flash Type 8-Bit MCU with LCD & EEPRO

Operating Mode Switching and Wake-up

The device can switch between operating modes dynamically allowing the user to select the best

performance/power ratio for the present task in hand. In this way microcontroller operations that do

not require high performance can be executed using slower clocks thus requiring less operating

current and prolonging battery life in portable applications.

In simple terms, Mode Switching between the NORMAL Mode and SLOW Mode is executed using

the HLCLK bit and CKS2~CKS0 bits in the SMOD register while Mode Switching from the

NORMAL/SLOW Modes to the SLEEP/IDLE Modes is executed via the HALT instruction. When a

HALT instruction is executed, whether the device enters the IDLE Mode or the SLEEP Mode is

determined by the condition of the IDLEN bit in the SMOD register and FSYSON in the WDTC

When the HLCLK bit switches to a low level, which implies that clock source is switched from the

high speed clock source, fH, to the clock source, fH/2~fH/64 or fL. If the clock is from the fL, the high

speed clock source will stop running to conserve power. When this happens it must be noted that the

fH/16 and fH/64 internal clock sources will also stop running, which may affect the operation of other

internal functions such as the TMs and the SIM. The accompanying flowchart shows what happens

when the device moves between the various operating modes.

NORMAL Mode to SLOW Mode Switching

When running in the NORMAL Mode, which uses the high speed system oscillator, and therefore

consumes more power, the system clock can switch to run in the SLOW Mode by set the HLCLK

bit to "0" and set the CKS2~CKS0 bits to "000" or "001" in the SMOD register. This will then use

the low speed system oscillator which will consume less power. Users may decide to do this for

certain operations which do not require high performance and can subsequently reduce power

consumption.

The SLOW Mode is sourced from the LXT or the LIRC oscillators and therefore requires these

oscillators to be stable before full mode switching occurs. This is monitored using the LTO bit in the

SMOD register.

HT67F60 датащи(PDF) 64 Page - Holtek Semiconductor Inc