# ADC16

## Overview

- This example shows ADC16 conversions and results in four working modes.

Notes:

* When ADC is configured to non-bus-read (oneshot) mode, it can't be accessed otherwise bus will be stuck.
* When ADC is configured to bus-read (oneshot) mode,  CPU has to complete initialization before accessing to the ADC register list.

## Board Setting

- Input voltage at the specified pin. （Please refer to  [Pin Description](lab_board_resource)）
- If necessary, connect a jumper for VREF pin according to the HW design. （Please refer to  [Pin Description](lab_board_resource)）

Note:  The input voltage range at ADC input pins: 0~VREFH

## Running the example

- Running log is shown in the serial terminal as follows

```console
This is an ADC16 demo:
1. Oneshot    mode
2. Period     mode
3. Sequence   mode
4. Preemption mode
Please enter one of ADC conversion modes above (e.g. 1 or 2 ...):
```

- Select one of ADC working modes to start ADC conversion,  and then watch conversion results

  - Oneshot mode

  ```console
  Please enter one of ADC conversion modes above (e.g. 1 or 2 ...): 1
  Oneshot Mode - ADC3 [channel 2] - Result: 0xffe8
  Oneshot Mode - ADC3 [channel 2] - Result: 0xfff4
  Oneshot Mode - ADC3 [channel 2] - Result: 0xffff
  ```

  - Period mode

  ```console
  Please enter one of ADC conversion modes above (e.g. 1 or 2 ...): 2
  Period Mode - ADC3 [channel 2] - Result: 0xfff3
  Period Mode - ADC3 [channel 2] - Result: 0xfff5
  Period Mode - ADC3 [channel 2] - Result: 0xfff7
  ```

  - Sequence mode

  ```console
  Please enter one of ADC conversion modes above (e.g. 1 or 2 ...): 3
  Sequence Mode - ADC3 - Cycle Bit: 01 - Sequence Number:00 - ADC Channel: 02 - Result: 0xffff
  Sequence Mode - ADC3 - Cycle Bit: 00 - Sequence Number:00 - ADC Channel: 02 - Result: 0xffd9
  Sequence Mode - ADC3 - Cycle Bit: 01 - Sequence Number:00 - ADC Channel: 02 - Result: 0xffff
  ```

  - Preemption mode

  ```console
  Please enter one of ADC conversion modes above (e.g. 1 or 2 ...): 4
  Preemption Mode - ADC3 - Trigger Channel: 00 - Cycle Bit: 01 - Sequence Number: 00 - ADC Channel: 02 - Result: 0xffff
  Preemption Mode - ADC3 - Trigger Channel: 00 - Cycle Bit: 01 - Sequence Number: 00 - ADC Channel: 02 - Result: 0xffff
  Preemption Mode - ADC3 - Trigger Channel: 00 - Cycle Bit: 01 - Sequence Number: 00 - ADC Channel: 02 - Result: 0xffff
  ```

## Note

- How to use WDOG feature

  - Channel initialization

    - Set ch_cfg. wdog_int_en to true
    - Set ch_cfg.thshdl/ch_cfg.thshdh

      The ch_cfg.thshdl/ch_cfg.thshdh can be configured from 0 to 65535. If any ADC conversion result is out of the thresholds (thshdl, thsdhh), a WDOG interrupt will occur.
  - Call adc16_init_channel () API.
  - ISR

    - Set one or more WDOG event flags depending on  ADC channels
    - Disable one or more corresponding WDOG interrupts
  - Main loop

    - Handle with WDOG events
    - Enable one or more corresponding WDOG interrupts
- Trigger source

  - In this sample, for sequence mode and preemption mode, PWM is selected as the trigger source. Other peripherals can also be selected as the trigger source.
  - The frequency of the trigger signal(20KHz by default) can be configured in sample-level CMakeLists.txt(e.g. sdk_compile_definitions(-DAPP_ADC16_TRIG_SRC_FREQUENCY=20000))
- Exception exit

  Press the "space" key to abort the test, and then a test mode can be reselected.