FM8PC71AM datasheet(25/73 Pages) FEELING

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FM8PC71AM

This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice.

No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product.

P.25

R1.1.004, Aug 7, 2017

FM8PC71AM

遠翔科技

Feeling Technology

2.5 Watchdog Timer(WDT)

The Watchdog Timer (WDT) is a free running on chip RC oscillator which does not require any external components.

So the WDT will still run into GREEN mode. During normal operation or in GREEN mode, a WDT time-out will cause

base on Configuration option to the device reset.

Configuration

WDTSEL[1:0]

VDD=5V~2.4V

SIRC = 32Khz, WDT Time out

2’b11

2’b10

2’b01

512 ms

2’b00

128 ms

The CLRWDT instruction clears the WDT, if assigned to the WDT, and prevents it from timing out and generating a

device reset.

The WDT can be disabled by clearing the control bit WDTE(11h-7). The WDT has a normal time-out period of 32ms

(without precaler). When the SLEEP instruction executes, the MCU will be reset or go next instruction on WDT

time-out.

The prescaler of WDT refers Table2.5-1.

The block diagram of WDT shows in Figure 2.5-2.

Address 11H: Watchdog Timer(WDT)

Bits

Name

WDTE

WDTSL

WDTPS[2:0]

LVRSL

Read/Write

R/W

Default

Bit[7] : WDTE

Watch-Dog timer enable.

1 = Enable.

0 = Disable.

Bit[6] : WDTSL

Watch-dog timer out selects.

1 = If Watch-dog timer out, the Device be reset. (PC = 0000h)

0 = If Watch-dog timer out, Device be wake up and PC = PC+1. (GRN_MD bit in 12h register be clear)

Bit[5:3] : WDTPS[2:0]

WDT Prescaler, please refer Table 2.5-1.

WDTPS[2:0]

WDT time out(config = 32ms)

3’b000

32ms*1

= 32

3’b001

32ms*2

= 64

3’b010

32ms *4

= 128 ms

3’b011

32ms *8

= 256 ms

3’b100

32ms *16

= 512 ms

3’b101

32ms *32

= 1024 ms

3’b110

32ms *64

= 2048 ms

3’b111

32ms *128 = 4096 ms

TABLE 2.6-1 WDT Prescaler

Bit[2] : LVRSL

LVR select.

1 = When Device is in green mode, the LVR signal can wake up to normal mode(PC=PC+1).

0 = When Device is in green mode, the LVR signal will be reset chip(PC=0x000).

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