nRF51822 ADC without UART

[Bombo]

I am using the adc to sample a sensor and send this over the air. For testing I used the simple_uart library and it works. But now I don't need the uart connection and I removed it from the project, but now the adc always returns 0.

I don't need have to send something over the uart, but I need to run "simple_uart_config()", to make the adc work. without it it won't work.

[Alex]

Must be one of the simple coding mistakes such as:

1. Variable sent over the air modified in one of the UART functions.
2. ADC restarted in UART function.

[Bombo]

I don't send data over the UART, only over the air. If I enable the UART it will be the first function in the main function.

[Bombo]

I think I found it. There needs to be a small delay between the start task and the check for busy.

uint16_t ADC_Read(void)
{
NRF_ADC->TASKS_START = 1;
__NOP(); // Delay to get the adc started
while(NRF_ADC->BUSY == 1)
{
}
NRF_ADC->TASKS_STOP = 1;
return NRF_ADC->RESULT;
}

The UART did somehow delay the CPU.

[jing]

I think the appropriate fix is to wait for the END event before reading the RESULT.

while (NRF_ADC->EVENTS_END == 0)
{
}