Re: Output Pin Oscillating

[John Kennedy]

I have written my 2nd Program for the 16C710 and have encountered output pins oscillating when given the output_low or output_high command. I have 10K pullups to the 5V rail on each pin. I'm using a 200Khz RC Oscillator the frequency the output pins oscillate at is 3.9Khz does anyone have any idea how to correct this. I have included a portion of the code that I have used to see if you can spot what I'm missing.

#define connect 125
#define vmin 50
#define minamp 3
#define almost 72
int batt,volt,amp;
int charged();

void main() {

setup_adc_ports(ALL_ANALOG);
setup_adc(ADC_CLOCK_DIV_2);
setup_counters(RTCC_INTERNAL,RTCC_DIV_2);

start:

output_high(PIN_B1);
output_high(PIN_B2);
output_high(PIN_B3);
output_high(PIN_B4);
output_high(PIN_B5);
output_low(PIN_B6); //pin works as it should here

do
{
set_adc_channel(0);
delay_us(100);
batt = read_adc();
}
while (batt > connect);

output_high(PIN_B6);

do
{
set_adc_channel(1);
delay_us(100);
volt = read_adc();
}
while (volt < vmin);
//all these pins oscillate at this point
output_low(PIN_B1);
output_low(PIN_B2);
output_low(PIN_B4);


Any help appreciated

Thanks

John Kennedy
___________________________
This message was ported from CCS's old forum
Original Post ID: 982

[PCM programmer]

:=I have written my 2nd Program for the 16C710 and have encountered output pins oscillating when given the output_low or output_high command.
----------------------------------------------------------

What do you have connected to each of the port B pins ?
(list all components).
___________________________
This message was ported from CCS's old forum
Original Post ID: 986

[John Kennedy]

:=I have written my 2nd Program for the 16C710 and have encountered output pins oscillating when given the output_low or output_high command. I have 10K pullups to the 5V rail on each pin. I'm using a 200Khz RC Oscillator the frequency the output pins oscillate at is 3.9Khz does anyone have any idea how to correct this. I have included a portion of the code that I have used to see if you can spot what I'm missing.
:=
:=#define connect 125
:=#define vmin 50
:=#define minamp 3
:=#define almost 72
:=int batt,volt,amp;
:=int charged();
:=
:=void main() {
:=
:= setup_adc_ports(ALL_ANALOG);
:= setup_adc(ADC_CLOCK_DIV_2);
:= setup_counters(RTCC_INTERNAL,RTCC_DIV_2);
:=
:=start:
:=
:= output_high(PIN_B1);
:= output_high(PIN_B2);
:= output_high(PIN_B3);
:= output_high(PIN_B4);
:= output_high(PIN_B5);
:= output_low(PIN_B6); //pin works as it should here
:=
:= do
:= {
:= set_adc_channel(0);
:= delay_us(100);
:= batt = read_adc();
:= }
:= while (batt > connect);
:=
:= output_high(PIN_B6);
:=
:= do
:= {
:= set_adc_channel(1);
:= delay_us(100);
:= volt = read_adc();
:= }
:= while (volt < vmin);
:=//all these pins oscillate at this point
:= output_low(PIN_B1);
:= output_low(PIN_B2);
:= output_low(PIN_B4);
:=
:=
:=Any help appreciated
:=
:=Thanks
:=
:=John Kennedy


----------------------------------------------------------

I don't have anything at the moment only a 10K pullup resistor to the 5V rail. I'm just testing the program to get it to do what I want it to. When it works the pins will be connected as follows.

RB1 - series 4k7 resistor to a gate of a 2N7000 signal mosfet.
RB2 - connected to the reset pin of a HEF4521 binary counter.
RB3 - connected to the output pin of the HEF4521.
RB4 - Cathode of an LED(LED on when pin low).
RB5 - as RB4.

All other pins floating.

If you can see any other potential problems please let me know.
___________________________
This message was ported from CCS's old forum
Original Post ID: 995

[Sherpa Doug]

:= while (volt < vmin);
:=//all these pins oscillate at this point
:= output_low(PIN_B1);
:= output_low(PIN_B2);
:= output_low(PIN_B4);

Is your +5 supply stable? Maybe one of these outputs is shorted to +5, or one of the pullups is much smaller than 10k, and the output going low causes the processor to hiccup. Try only setting one pin at a time to see which one is the culprit.
___________________________
This message was ported from CCS's old forum
Original Post ID: 1000