ADC Manager Mode

This sample code guide is designed to help users easily and comprehensively understand ADC sample. This sample demonstrates how ADC samples data by ADC manager. This sample uses one shot mode of the ADC peripheral to measure voltage on VBAT and VADP by ADC manager.

Requirements

For hardware requirements, please refer to the Requirements.

Wiring

1. Connect Lithium-ion battery to EVB.

2. Connect VADP to 5V of EVB.

Configurations

1. The following macros can be configured to modify the sampling period.

   • #define TEST_CYCLE (3)

2. The following macros can be configured to modify the number of samples per sampling cycle.

   • #define TEST_COUNT (100)

3. The entry function is as follows, call this function in main() to run this sample code. For more details, please refer to the Initialization.

   adc_manager_demo();
   

Building and Downloading

For building and downloading, please refer to the Building and Downloading.

Experimental Verification

Press the Reset button on the EVB board, ADC samples every 100ms, there are three sampling cycles, and each sampling cycle samples 100 times. Once ADC sampling is finished, the raw data collected and the converted voltage values will be printed in Debug Analyzer.

adc_cb: seq xxx, adc_data[0] xxx, adc_data[1] xxx

Code Overview

This section introduces the code and process description for initialization and corresponding function implementation in the sample. When the internal charger is enabled, it is necessary to use ADC manager mode for ADC sampling.

Source Code Directory

• For project directory, please refer to Source Code Directory.

• Source code directory: sdk\src\sample\io_demo\adc\adc_manger\adc_manager_demo.c.

Initialization

The initialization flow of ADC sampling in one shot mode by ADC manager is shown in the following figure.

ADC One Shot Sampling by ADC Manager Mode

1. Initialize the ADC peripheral:

   1. Define the ADC_InitTypeDef type ADC_InitStruct, and call ADC_StructInit() to pre-fill ADC_InitStruct with default values.

   2. Modify the ADC_InitStruct parameters as needed. The ADC initialization parameter configuration is shown in the table below.

   3. Call adc_mgr_register_req() to request for a channel in ADC manager and initialize the ADC peripheral.

   ADC Initialization Parameters

   ADC Hardware Parameters	Setting in the ADC_InitStruct Variables	ADC
   Sample Time	ADC_InitTypeDef::adcClock	ADC_CLK_39K
   Bit Map	ADC_InitTypeDef::bitmap	0x0003
   Schedule Index	ADC_InitTypeDef::schIndex	Index 0 is set to INTERNAL_VBAT_MODE. Index 1 is set to INTERNAL_VADPIN_MODE.

2. Call adc_mgr_enable_req() to enable the specific ADC manager channel for sampling.

Functional Implementation

Callback Handle

When ADC sampling is completed, ADC manager callback function will be executed. ADC manager callback handle flow is shown in the following figure.

ADC Manager Callback Handle Flow

1. Call adc_mgr_read_data_req() to read ADC sampling raw data of the specific ADC manager channel.