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9 years, 2 months ago.
AnalogIn does not recognize the Ain(A0)
Hi all I just starting learning ARM programming, I am using the ST32F401R board and run blinky ok, but tried to read analog for potentiometer wiper (25k ohm pot terminals connected GND , +3.3v and wiper to PA_0 as A0 ) the LED is always off, any help highly appreciated.
- include "mbed.h"
AnalogIn analog_value(A0);
DigitalOut myled(LED1);
Calculate the corresponding acquisition measure for a given value in mV
- define MV(x) ((0xFFF*x)/3300)
int main() { while(1) { uint16_t meas = analog_value.read_u16(); Converts and read the analog input value if (meas > MV(1000)) { If the value is greater than 1000 mV toggle the LED myled = !myled; } wait(0.2); 200 ms } }
2 Answers
9 years, 1 month ago.
I have the same problem,that's a bug,please see http://developer.mbed.org/questions/4420/Problem-with-Nucleo-L152RE-AnalogIn/ ,but unfortunately,it has not been fixed!
9 years, 1 month ago.
There is a bug with the HSI clock in the Nucleos with F053R8, which is still to be fixed. But I just checked exactly your configuration (F401RE as well as F103RB) and ran the program successfully. The LED only flashes if read_u16() is bigger than the calculated value. Please double-check if the most recent ST-LINK firmware is programmed, e.g. using ST-LINK/V2-1 firmware upgrade
BTW: the 1000mV is calculated incorrectly, as read_u16() got a range of 16bit and not just 12bit. But that's not the reason of your problem! So please change
define MV(x) ((0xFFF*x)/3300)
to
define MV(x) ((0xFFFF*x)/3300)
Thanks ,I tried that, still does not recognize the A0 !
posted by Mohammed Shalash 03 Feb 2015It is ok now after updating the STM32f401R firmware. THANKS
posted by Mohammed Shalash 03 Feb 2015