Information

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller SPDIP 28 16-Bit 40 null I/O number 21

 2012-2013 Microchip Technology Inc. DS80000540E-page 7

dsPIC33FJ06GS001/101A/102A/202A and dsPIC33FJ09GS302

12. Module: Comparator

The comparator and DAC modules do not function

when both of the following are true:

• the External Voltage Reference is selected

(EXTREF = 1), and

• the external voltage reference is less than

1.6V.

Work around

Use the INTREF or AVDD/2 references, whenever

possible.

If the External Voltage Reference must be used,

be aware that the published specifications for

EXTREF define an input voltage range of 0V

minimum and (AV

DD – 1.6)V maximum. For the

affected silicon revisions, the operational input

voltage limits of EXTREF are 1.6V minimum and

(AV

DD – 0.6)V maximum.

Affected Silicon Revisions

13. Module: PWM

The PWMx generator may not assert dead time on

the edges of transitions. This has been observed

when all of the following conditions are present:

• The PWMx generator is configured to operate

in Complementary mode with the

independent time base or master time base;

• Immediate update is enabled; and

• The value in the PDCx register is updated in

such a manner that the PWMxH and PWMxL

outputs make an immediate transition.

The current duty cycle, PDC

OLD, newly calculated

duty cycle, PDC

NEW, and the point at which the

write to the Duty Cycle register occurs within the

PWMx time base, will determine if the PWMxH and

PWMxL outputs make an immediate transition.

PWMxH and PWMxL outputs make an immediate

transition if the Duty Cycle register is written with a

new value, PDC

NEW, at a point of time when the

PWMx time base is counting a value that is in

between PDC

NEW and PDCOLD. Additionally,

writing to the Duty Cycle register close to the

instant of time where dead time is being applied

may result in reduced dead time, effective on the

PWMxH and PWMxL transition edges.

In Figure 1 (following page), if the duty cycle write

occurred in the shaded box, then PWMxH and

PWMxL will make an immediate transition without

dead time.

Work around

None. However, in most applications the duty

cycle update timing can be controlled using the

TRIGx trigger or Special Event Trigger such that

the above mentioned conditions are avoided

altogether.

Affected Silicon Revisions