HT9480 datasheet(36/57 Pages) HOLTEK

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Mask option

The following table illustrates nine kinds of mask options in the HT9480. All of the options should

be defined to ensure proper system functioning.

No.

Mask Option

HALT function selection. This option defines the way of enabling or disabling the HALT

function.

WDT source selection. This option selects the WDT source, from either the subsystem clock,

or instruction clock, or disabling the WDT function.

CLRWDT times selection. This option defines the way of clearing the WDT by instruction.

“Once” means that the “CLR WDT” can clear the WDT and “Twice” implies that the “CLR

WDT1” and “CLR WDT2” should be executed before the time-out so as to clear the WDT.

Wake-up selection. This option defines the wake-up activity. Port A has the capability of

waking-up the chip from HALT.

PB, PC0, and PC1 pull-high options

µC OSC type selection. This option is to decide if an RC or Crystal oscillator is chosen as

the system clock.

WDT prescaler selection. The prescaler can be set to 1/1024 or 1/2048

FOUT connection selection. The FOUT output can be connected to the OSC1 input or not.

Double frequency selection. The FOUT can be doubled from the X1 input clock.

HT9480

23th Feb ’98

HT9480 Datasheet(PDF) 36 Page - Holtek Semiconductor Inc