adc: adc_read() not check for error (#1575) v2 #1599
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Implementation of adc_read() not check for errors in the ADC_CS register.
- change the return type from uint16_t to int32_t
- check for ADC_CS_READY_BITS and error ADC_CS_ERR_BITS or ADC_CS_ERR_STICKY_BITS
- return the ADC value (12bits) or the negative value of
ADC_CS_ERR_BITS or ADC_CS_ERR_STICKY_BITS depending on the error
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| return (uint16_t) adc_hw->result; | ||
| if ((adc_hw->cs & ADC_CS_READY_BITS)>0) { | ||
| return adc_hw->result & 0xfff; |
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Might be better to use ADC_RESULT_BITS
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I will have a look if that will have benefit. The original code check for the ADC_CS_READY_BITS.
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I believe Peter meant use ADC_RESULT_BITS instead of 0xfff - see https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2040/hardware_regs/include/hardware/regs/adc.h#L111
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Oh, :)
Thanks for the eye opener.
| return adc_hw->result & 0xfff; | ||
| } | ||
| if ((adc_hw->cs & ADC_CS_ERR_BITS)>0) { | ||
| return -ADC_CS_ERR_BITS; |
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It's a bit random to return -ADC_CS_ERR_BITS. It would be better to return a "standard" error code? Maybe PICO_ERROR_GENERIC or PICO_ERROR_NO_DATA?
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I see your point, but if we doing this we can't distinguished what caused the error.
Use
PICO_ERROR_NO_DATA
and additional, define a new code:
PICO_ERROR_ADC_STICKY_BIT
| } | ||
| /* clear sticky bit */ | ||
| hw_set_bits(&adc_hw->cs, ADC_CS_ERR_STICKY_BITS); | ||
| return -ADC_CS_ERR_STICKY_BITS; |
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same comment as above
Implementation of adc_read() not check for errors in the ADC_CS register.
v2: