PIC12F617T-EMD View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC12F617T-EMD

8-Pin Flash-Based, 8-Bit CMOS Microcontrollers

Microchip Technology 

PIC12F609/615/617/12HV609/615

11.4.4

ENHANCED PWM AUTO-

SHUTDOWN MODE

The PWM mode supports an Auto-Shutdown mode that

will disable the PWM outputs when an external

shutdown event occurs. Auto-Shutdown mode places

the PWM output pins into a predetermined state. This

mode is used to help prevent the PWM from damaging

the application.

The auto-shutdown sources are selected using the

ECCPASx bits of the ECCPAS register. A shutdown

event may be generated by:

• A logic ‘0’ on the INT pin

• Comparator

• Setting the ECCPASE bit in firmware

A shutdown condition is indicated by the ECCPASE

(Auto-Shutdown Event Status) bit of the ECCPAS

register. If the bit is a ‘0’, the PWM pins are operating

normally. If the bit is a ‘1’, the PWM outputs are in the

shutdown state. Refer to Figure 1.

When a shutdown event occurs, two things happen:

The ECCPASE bit is set to ‘1’. The ECCPASE will

remain set until cleared in firmware or an auto-restart

occurs (see Section 11.4.5 “Auto-Restart Mode”).

The enabled PWM pins are asynchronously placed in

their shutdown states. The state of P1A is determined by

the PSSAC bit. The state of P1B is determined by the

PSSBD bit. The PSSAC and PSSBD bits are located in

the ECCPAS register. Each pin may be placed into one

of three states:

• Drive logic ‘1’

• Drive logic ‘0’

• Tri-state (high-impedance)

FIGURE 11-10: AUTO-SHUTDOWN BLOCK DIAGRAM

ECCPAS<2:0>

INT

From Comparator

111

110

101

100

011

010

001

000

PRSEN

PSSAC<0> 1

P1A_DRV

0

PSSAC<1>

RS

P1A

TRISx

From Data Bus

D Q ECCPASE

Write to ECCPASE

PSSBD<0> 1

P1B_DRV

0

PSSBD<1>

P1B

TRISx

 2010 Microchip Technology Inc.

DS41302D-page 101

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