int main()
{
set_analog_mode(MODE_8_BIT); // 8-bit analog-to-digital conversions
sum = 0;
samples = 0;
avg = 0;
start_analog_conversion(TRIMPOT); // start initial conversion
while(1)
{
if (!analog_is_converting()) // if conversion is done...
{
sum += analog_conversion_result(); // get result
start_analog_conversion(TRIMPOT); // start next conversion
if (++samples == 20) // if 20 samples have been taken...
{
avg = sum / 20; // compute 20-sample average of ADC result
samples = 0;
sum = 0;
}
}
// when avg == 0, the red LED is almost totally off.
// when avg == 255, the red LED is almost totally on.
// brightness should scale approximately linearly in between.
red_led(0); // red LED off
delay_us(256 - avg);
red_led(1); // red LED on
delay_us(avg+1);
}
}
void test_analog()
{
// test that set/get mode works
set_analog_mode(MODE_8_BIT);
printf("\nGet8BIT");
assert(MODE_8_BIT == get_analog_mode());
set_analog_mode(MODE_10_BIT);
printf("\nGet10BIT");
assert(MODE_10_BIT == get_analog_mode());
// read the trimpot in 10 bit mode and compare it to 8 bit mode
int x1 = analog_read(7);
set_analog_mode(MODE_8_BIT);
delay_ms(1); // required for readings to stabilize
int x2 = analog_read(7);
printf("\n8BIT10BIT %d %d",x1,x2);
assert( abs((x1>>2) - x2) < 10 );
// make sure that the average reading is more stable than individual readings
set_analog_mode(MODE_10_BIT);
unsigned char i;
int min = 1023, max = 0, avg_min = 1023, avg_max = 0;
for(i=0;i<10;i++)
{
int x1 = analog_read(7);
int x2 = analog_read_average(7,256);
if(x1 > max) max = x1;
if(x1 < min) min = x1;
if(x2 > avg_max) avg_max = x2;
if(x2 < avg_min) avg_min = x2;
printf("\nAvgComp %03x %03x", x1, x2);
assert( abs(x1-x2) < 10);
}
printf("\nAB%03x%03x%03x%03x",max,min,avg_max,avg_min);
assert( max - min >= avg_max - avg_min);
// check that temp C and F return appropriate values in 10bit mode
set_analog_mode(MODE_10_BIT);
x1 = analog_read_average(6,100);
int expect_temp_f = (((int)(analog_read_average_millivolts(TEMP_SENSOR, 20)) * 12) - 634) / 13;
int expect_temp_c = (((int)(analog_read_average_millivolts(TEMP_SENSOR, 20) * 20)) - 7982) / 39;
int temp_f = read_temperature_f();
int temp_c = read_temperature_c();
printf("\nTF10 %d %d", expect_temp_f, temp_f);
assert( expect_temp_f/5 == temp_f/5 );
printf("\nTC10 %d %d", expect_temp_c, temp_c);
assert( expect_temp_c/5 == temp_c/5 );
// try temp in 8bit mode
set_analog_mode(MODE_8_BIT);
delay_ms(1); // required for readings to stabilize?
temp_f = read_temperature_f();
temp_c = read_temperature_c();
printf("\nTF8 %d %d", expect_temp_f, temp_f);
assert( (expect_temp_f - temp_f) <= 20 );
printf("\nTC8 %d %d", expect_temp_c, temp_c);
assert( abs(expect_temp_c - temp_c) <= 20 );
// test background conversion
set_analog_mode(MODE_10_BIT);
delay_ms(1); // required for readings to stabilize
x1 = analog_read_average(6,100);
start_analog_conversion(6);
while(analog_is_converting())
printf("\nConvert");
x2 = analog_conversion_result();
printf("%d %d", x1, x2);
assert( abs(x1 - x2) < 10 );
// make sure to_millivolts works in 8 and 10 bit mode
set_analog_mode(MODE_10_BIT);
x1 = 5000;
x2 = to_millivolts(1023);
printf("\nmV1 %d %d",x1,x2);
assert( x1 == x2 );
x1 = 2498;
x2 = to_millivolts(511);
printf("\nmV2 %d %d",x1,x2);
assert( x1 == x2 );
x1 = 0;
x2 = to_millivolts(0);
printf("\nmV3 %d %d",x1,x2);
assert( x1 == x2 );
set_analog_mode(MODE_8_BIT);
x1 = 5000;
x2 = to_millivolts(255);
printf("\nmV4 %d %d",x1,x2);
assert( x1 == x2 );
x1 = 2490;
x2 = to_millivolts(127);
printf("\nmV5 %d %d",x1,x2);
assert( x1 == x2 );
x1 = 0;
x2 = to_millivolts(0);
printf("\nmV6 %d %d",x1,x2);
assert( x1 == x2 );
}