Compiler/CC2541: ADC Read and Battery Percentage

What is your question?

my question is, the ADC value I'm getting is obviously wrong as I mentioned the code and the output above. In the Android APP I'm using, the battery percentage showing is 100 percent. 

The ADC Values are not correct, then how I'm getting 100% battery whereas in reality battery is 50% available. 

Even though I tried, adc = HalAdcRead(HAL_ADC_CHN_AIN7, HAL_ADC_RESOLUTION_12); //P0.7 but same result. 

Regards,

Yatin Baluja  

Try to use power supply to give 1V to ADC input pin and make sure you can read correct ADC reading first.

I tested that now, giving 1V from extenal power supply. Same result like 

adc: 4

adc: 3

adc: 2

adc: 1

That’s not possible. Do you use multi-meter to check the physical voltage on ADC pin?

Hi Yatin,

I assume you have referenced YK's blog but please also refer to the CC2531 Peripheral Software Examples.

Regards,
Ryan

Hi YiKai Chen, 

I have two PINS with CC2541. One PIN is P0_7 and other PIN is P0_3. I want to define P0_7 as input GPIO PIN and P0_3 as output GPIO PIN. How would I declare these as desired. 

Regards,

Yatin Baluja 

You can use the following codes to set P0_7 as input GPIO PIN and P0_3 as output GPIO PIN.

P0SEL&=!(BV(7)|BV(3));

P0DIR |=  BV(3);

P0DIR &=!BV(7);

okay and what if I want to read the analog value from these PINS, specially P0_7 PIN which is going to be the input pin and I want to read the analog value 

as I want to read the Analog Value of P0_7 PIN for the ADC but I don't know how to set the PIN as input and read the analog value for the ADC at P0_7 PIN

If you use BLE-STACK, you can use API HalAdcRead(HAL_ADC_CHN_AIN7, ...) to do ADC reading on P0.7.

By the way, do you define HAL_ADC=TRUE in your project to make ADC driver work?

Yes, in Pre processor I defined HAL_ADC = TRUE;

Hi YiKai Chen,

void ADC_handle(void)

{
    P0SEL&=!(BV(7));

   P0DIR &=!BV(7);  

   uint16 adc=0;

   adc = HalAdcRead(HAL_ADC_CHN_AIN7, HAL_ADC_RESOLUTION_12); //P0.7

   printf("ADC Value: %d'\n'",adc);

}

why I'm getting an output like this

ADC Value: 4

ADC Value: 3

ADC Value: 2

ADC Value: 1

I'm not getting this. 

Regards,

Yatin Baluja

Please remove "P0SEL&=!(BV(7));" and "P0DIR &=!BV(7);" before you call HalAdcRead to do ADC reading.

removed and checked. 

same output. 

void ADC_handle(void)

{

   uint16 adc=0;

   adc = HalAdcRead(HAL_ADC_CHN_AIN7, HAL_ADC_RESOLUTION_12); //P0.7

   printf("ADC Value: %d'\n'",adc);

}

ADC Value: 4

ADC Value: 3

ADC Value: 2

ADC Value: 1

What is the voltage on your P0.7 if you use scope to check it?

I have two resistors each of 10K connected with P0_7 PIN. I'm going to check the voltage at both the resistors. 

I would suggest you to remove everything connecting to P0.7 and use power supply to give 1.0V to P0.7 directly to do ADC reading first.

okay but to check the reading. I need to connect the CC2541 debugger to check the print statement and the value.

Yes, using CC debugger and IAR debug are the easiest way to check the ADC reading.

Couldn't see your attached video.

Now I think you can see the video. 

I cannot see detail of your CC2541 board connection from your video. I just test P0.7 to do ADC reading on my TICC2541DK and I am pretty sure it works fine. I use the following codes for your reference.

uint16 adc;

  HalAdcSetReference(HAL_ADC_REF_125V);
  
  while(1)
  {
    adc=HalAdcRead(HAL_ADC_CHN_AIN7,HAL_ADC_RESOLUTION_10);
  }

I have the custom PCBA. I cannot take or insert any part from the PCBA. 

I think there must be something wrong on your custom board. I can only suggest you to debug your hardware first.

uint16 adc;

  HalAdcSetReference(HAL_ADC_REF_125V);
  
  while(1)
  {
    adc=HalAdcRead(HAL_ADC_CHN_AIN7,HAL_ADC_RESOLUTION_10);
  }


with this. I'm getting on value "4" as an ADC value

It means that your P0.7 connect to almost 0V.

Is there any way to solve this ??

Do you check your hardware? By the way, do you design the hardware by yourself or buy it from 3rd party?

It's a 3rd party design as my client made this and forward to me

Hi YiKai Chen,

using below code. I am getting ADC Value: 5632 if I connect the battery on P0_7 or not, I'm getting this output. "ADC Value: 5632"

void adc_Init(void)
{
//APCFG |=0x84;
//P0SEL |= 0x84;
//P0DIR &= ~0x84;
P0SEL&=!(BV(7));
P0DIR &=!BV(7);
}
/******************************************************************************
*Function:Read_advalue
*Decription:ADCRead
*Input:Conversion channel
*Output:ADC conversion result
******************************************************************************/
uint16 Read_advalue(uint8 channel)
{
uint16 value=0;
uint16 value_bak=0;

APCFG |= 1 << channel ; //Set ADC input channel, set to analog I / O port
ADCIF = 0;
ADCCON3 = (HAL_ADC_REF_VDD5 | ADC_12_BIT | ADC_EMP_SENS); //Select AVDD5 as the reference voltage; 12-bit resolution; sample AIN7

while(!ADCIF); //Wait for AD conversion to complete

value = ADCL;
value_bak=ADCH;
value_bak <<=5;
value_bak &=0xffc0;
value=value_bak|value;

return value;
}
/**********************************************************************
* Function:sort_up
* Decription:Sort
* Input: no
* Output:no
***********************************************************************/
void sort_up(void)
{
uint8 n,m;
uint16 tt;
for(m = 0;m < BAT_num;m++)
{
for(n = 0;n < BAT_num-m;n++)
{
if(adc_data[n] > adc_data[n+1])
{
tt = adc_data[n];
adc_data[n] = adc_data[n+1];
adc_data[n+1] = tt;
}
}
}
}
/***************************************************************
Function:Battery_ADC_Check
Decription:Continuous sampling
Input:No
Output: AD value
****************************************************************/
uint16 Battery_ADC_Check(void)
{
uint16 i,n;
uint16 k=0;
for(i=0; i<BAT_num; i++)
{
adc_data[i]= Read_advalue(7);
DelayMS(100);
}
sort_up();

for(n=1; n<BAT_num-1; n++)
{
k +=adc_data[n];
}
k=k/(BAT_num-2);

return k;
}

void ADC_handle(void)
{
adc_value = Battery_ADC_Check();
printf("ADC Value: %d'\n'",adc_value);

}

Please make sure you can do correct ADC reading using my example code first. It's meaningless to check your code for now.

ok

using your code, I'm getting ADC Value: 4 and I'm going to message manufacturer to check 

Hi YiKai Chen, I contacted my client who manufactured this PCBA and waiting for their reply. 

I have a few questions to ask regarding push button functionality with CC2541. 

I have 4 push buttons. Connected with CC2541 at P0_3, P0_5, P0_1 and P0_7. 

Now what I want is, pressing P0_3 for 2-3 seconds will turn ON the device, again if I press the same button again that will select one LED (RED) this will not turn ON the led just select the LED. similarly, if I press the P0_5 button then orange LED will select but if I press P0_7 button then the RED LED (P0_3) and orange LED (P0_5) selected previously will turn ON those selected LED's or push buttons. 

Basically selecting the buttons but turning ON those buttons pressing the last fourth button. 

How I will proceed in this.

Regards,

Yatin Baluja 

You can refer to hal_key.c to know how to process it.

ok. YiKai Chen as in simpleBLEPeripheral example we have pre-defined bluetooth UUID as 00FF can I change that to 00EE because I tested 00GG but that wasn't working. Though 00EE worked. Is there any limit defining UUID as I'm able to use 00EE but not 00GG.

Regards,

Yatin Baluja

UUIDis in hex format and GG is out out boundary.

Hi YiKai Chen, can I use 3.3v as voltage reference for the ADC ??  

like this                   #define HAL_ADC_REF_VDD5                0x80

Regards,

Yatin Baluja

Yes.

I'm using that but I'm getting ADC value as 5632, no change in the value 

I remember you mentioned you would contact your module manufacturer. Have you solved your previous issue when reading ADC with internal reference?

I checked with them, they are saying hardware is fine as they calculated the voltage at connected resistors and it is coming fine. As it's a 12-bit ADC and they are using 10k and 20k voltage divider. They are not seeking any problem in the hardware. 

void ADC_handle(void)
{
uint16 adc_value;
HalAdcSetReference( HAL_ADC_REF_VDD5 );
while(1)
{
adc_value = HalAdcRead(HAL_ADC_CHN_AIN7,HAL_ADC_RESOLUTION_12);
printf("ADC Value: %d'\n'",adc_value);
}
}

I'm using this at present to read the value but I'm getting only "1". 

I see no problem in your codes. If you still cannot make it work, I am pretty sure there’s something wrong in your hardware.

Hi YiKai Chen

it is possible to send battery notification of a last reading as I don't want to send the notification regularly it's when the bluetooth gets connected with the device I want the last measured value will notify rather than notifying the current battery value 

Regards,

Yatin Baluja 

I suppose you can do anything you prefer in your application.