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Window watchdog (WWDG)

RM0016

 

 

15.6Hardware watchdog option

If hardware watchdog is selected by option byte, the watchdog is always active and the WDGA bit in the WWDG_CR register is not used. Refer to the option byte description in the datasheet.

15.7Using Halt mode with the WWDG (WWDGHALT option)

The following recommendation applies if Halt mode is used when the watchdog is enabled.

Before executing the HALT instruction, refresh the WDG counter, to avoid an unexpected WWDG reset immediately after waking up the microcontroller.

15.8WWDG interrupts

None.

15.9WWDG registers

15.9.1Control register (WWDG_CR)

Address offset: 0x00

Reset value: 0x7F

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

WDGA

T6

T5

T4

T3

T2

T1

T0

 

 

 

 

 

 

 

 

rs

rw

rw

rw

rw

rw

rw

rw

 

 

 

 

 

 

 

 

Bit 7 WDGA: Activation bit(1)

This bit is set by software and only cleared by hardware after a reset. When WDGA = 1, the watchdog can generate a reset.

0:Watchdog disabled

1:Watchdog enabled

Bits 6:0 T[6:0]: 7-bit counter (MSB to LSB)

These bits contain the value of the watchdog counter. It is decremented every 12288 fCPU cycles (approximately). A reset is produced when it rolls over from 0x40 to 0x3F (T6 becomes cleared).

1. This bit is not used if the hardware watchdog option is enabled by option byte.

15.9.2Window register (WWDG_WR)

Address offset: 0x01

Reset value: 0x7F

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

Reserved

W6

W5

W4

W3

W2

W1

W0

 

 

 

 

 

 

 

rw

rw

rw

rw

rw

rw

rw

 

 

 

 

 

 

 

 

 

Bit 7 Reserved

130/454

Doc ID 14587 Rev 9

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