DM300023 Microchip Technology, DM300023 Datasheet - Page 15

• Manufacturer Part Number: DM300023
• Description: KIT DEMO DSPICDEM SMPS BUCK
• Manufacturer: Microchip Technology
• Series: dsPIC™r

Specifications of DM300023

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 2, Non-Isolated
• Voltage - Input: 7 ~ 15V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: dsPIC30F2020
• Processor To Be Evaluated: dsPIC30F202x/1010
• Interface Type: RS-232
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -
• Frequency - Switching: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

34. Module: PWM Override Priority
EQUATION 4:
35. Module: CPU –
EXAMPLE 3:
© 2008 Microchip Technology Inc.
L0:daw.b
L1: ....
The “dsPIC30F1010/202X Device Data Sheet”
(DS70178) states the priority of PWMx pin
ownership as:
• PWM Generator (lowest priority)
• Output Override
• Current-Limit Override
• Fault Override
• PENx (GPIO/PWM) ownership (highest priority)
Instead of following the above priority scheme, the
PWMx pin ownership is determined by ANDing the
Output Override Data bits (OVRDAT<1:0>),
Current-Limit Override Data bits (CLDAT<1:0>),
and Fault Override Data bits (FLTDAT<1:0>) in the
IOCONx register.
The Decimal Adjust instruction, DAW.b, may
improperly clear the Carry bit, C (SR<0>), when
executed.
Work around
Check the state of the Carry bit prior to executing
the DAW.b instruction. If the Carry bit is set, set the
Carry bit again after executing the DAW.b
instruction. Example 3 shows how the application
should process the Carry bit during a BCD addition
operation.
.include “p30fxxxx.inc”
.......
mov.b
mov.b
add.b
bra
daw.b
bset.b SR, #C
bra
#0x80, w0
#0x80, w1
w0, w1, w2 ;Perform addition
NC, L0
w2
L1
w2
PWMxH = (OVRDAT<1>) AND (CLDAT<1>) AND (FLTDAT<1>) = 0 AND 0 AND 1 = 0
PWMxL = (OVRDAT<0>) AND (CLDAT<0>) AND (FLTDAT<0>) = 0 AND 1 AND 0 = 0
CHECK CARRY BIT BEFORE
DAW.b
DAW.b
;First BCD number
;Second BCD number
;If C set go to L0
;If not, do DAW and
;set the carry bit
;and exit
instruction
dsPIC30F1010/202X
For example, the override data may be set as
follows:
• OVRDAT<1:0> = 00
• CLDAT<1:0> = 01
• FLTDAT<1:0> = 10
If all three overrides occur simultaneously, the
following operations shown in Equation 4 will
determine the state of the PWMx pin.
Therefore,
simultaneously, only the override data for the
active override sources will be ANDed together
while the inactive override sources will be ignored.
If only one override is active, override priorities do
not apply and operation of the PWM overrides is
normal.
Work around
None.
when
multiple
overrides
DS80290J-page 15
occur