Voltage Display

[jdasari]

Please bear with my beginners ignorance here.
Once I get the voltage reading using the read_adc( ) how can I convert that into the actual decimal voltage. i.e For e.x if I read 153 how can display that as 3 volts on the LCD? I have my code pasted below. Thanks much in advance.



void main()
{

int choice=1; int flag=0;
int8 bat_voltage;
float dig_voltage= 0;
lcd_init();
set_tris_a(0xFF);
setup_adc_ports(ALL_ANALOG);
setup_adc(ADC_CLOCK_DIV_32);


while (flag == 0)
{
set_adc_channel(1);
delay_us(100);
bat_voltage=read_adc();
printf(lcd_putc,"\f bat_voltage=\%u", bat_voltage);
if(bat_voltage >= 255)
{
lcd_putc (" \f Full Charge \n");
flag=1;
}
dig_voltage = (bat_voltage*5)/255;
printf(lcd_putc,"\n \%f", dig_voltage);
delay_ms(1000);
}

lcd_putc("\f Exiting \n");
while(1);

}
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This message was ported from CCS's old forum
Original Post ID: 13543

[Sherpa Doug]

:=Please bear with my beginners ignorance here.
:=Once I get the voltage reading using the read_adc( ) how can I convert that into the actual decimal voltage. i.e For e.x if I read 153 how can display that as 3 volts on the LCD? I have my code pasted below. Thanks much in advance.
:=
:=
:=
:=void main()
:={
:=
:=int choice=1; int flag=0;
:=int8 bat_voltage;
:=float dig_voltage= 0;
:=lcd_init();
:=set_tris_a(0xFF);
:=setup_adc_ports(ALL_ANALOG);
:=setup_adc(ADC_CLOCK_DIV_32);
:=
:=
:=while (flag == 0)
:={
:=set_adc_channel(1);
:=delay_us(100);
:=bat_voltage=read_adc();
:=printf(lcd_putc,"\f bat_voltage=\%u", bat_voltage);
:=if(bat_voltage >= 255)
:={
:=lcd_putc (" \f Full Charge \n");
:=flag=1;
:=}
:=dig_voltage = (bat_voltage*5)/255;
:=printf(lcd_putc,"\n \%f", dig_voltage);
:=delay_ms(1000);
:=}
:=
:=lcd_putc("\f Exiting \n");
:=while(1);
:=
:=}

Try:

dig_voltage = ((float)bat_voltage*5)/255;

Bat_voltage * 5 may not fit in an int8.
If that is not the problem could you tell us what results you do get?

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This message was ported from CCS's old forum
Original Post ID: 13547

[jdasari]

Thanks Sherpa....that worked
___________________________
This message was ported from CCS's old forum
Original Post ID: 13623