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WICED Studio Bluetooth

New Contributor II

hi,

CYW20819 is a single-ended switched-capacitor sigma-delta ADC with 12 bits for Audio* measurements and 10 bits for DC measurements.

The application need a 11 or 12 bit ADC for DC measurements, don't need hight conversion rate (10KHZ), is there a way to get 12 bit general ADC?

Regards,

Nicole

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Moderator
Moderator

Hi,

Q) The application need a 11 or 12 bit ADC for DC measurements, don't need hight conversion rate (10KHZ), is there a way to get 12 bit general ADC?

A) You can't configure it to 12 bit ADC. You may try using API  wiced_hal_adc_read_raw_sample ( 20819-A1_Bluetooth\include\20819\hal\wiced_hal_adc.h ) . It will give 16 bit raw value directly from the register. You can take the 12 bit value from that and can use in application as per your requirement.  Example : Code-Examples-BT-SDK-for-ModusToolbox/CYW920819EVB-02/apps/snip/hal at master · cypresssemiconductor...

Thanks,

Anjana

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Moderator
Moderator

The 12 bits ADC is only avaliable for audio mode in HID application. You can't use it for DC measurements.

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Moderator
Moderator

Hi,

Q) The application need a 11 or 12 bit ADC for DC measurements, don't need hight conversion rate (10KHZ), is there a way to get 12 bit general ADC?

A) You can't configure it to 12 bit ADC. You may try using API  wiced_hal_adc_read_raw_sample ( 20819-A1_Bluetooth\include\20819\hal\wiced_hal_adc.h ) . It will give 16 bit raw value directly from the register. You can take the 12 bit value from that and can use in application as per your requirement.  Example : Code-Examples-BT-SDK-for-ModusToolbox/CYW920819EVB-02/apps/snip/hal at master · cypresssemiconductor...

Thanks,

Anjana

View solution in original post

New Contributor II

hi,

I test HAL_ADC_mainapp  using CYW920819EVB-02.

remove J14 jump. using carbon film resistor connect 3v3 and A0 pin. but the ADC value is not 3.3v, is it ininternal resistor?

one 47k resistance connect 3v3(j11)  and A0(J12), the adc value is 3.0v

********************************************************************

Signed Raw Sample value of ADC_INPUT_P8 : 16556

Voltage equivalent of received sample(in mV) : 3001

FW Voltage value of ADC_INPUT_P8(in mV) : 3002

Two 47k resistor in parallel, connect 3v3(j11)  and A0(J12), the adc value is 3.15v

********************************************************************

Signed Raw Sample value of ADC_INPUT_P8 : 18493

Voltage equivalent of received sample(in mV) : 3153

FW Voltage value of ADC_INPUT_P8(in mV) : 3156

Thanks

Nicole

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Moderator
Moderator

Hi Nicole,

Yes, there is input impedance of 500Kohm  (I think which is making effective voltage as (3.3V*500k)/(47k+500k) = 3.01V) . Please refer to 10.9 ADC Electrical Characteristics in the datasheet https://www.cypress.com/documentation/datasheets/cyw20819-ultra-low-power-blebredr-bluetooth-50-soc

Thanks,

Anjana