sdk-bsp-rzn2l-etherkit/projects/etherkit_driver_adc

ADC Driver Usage Instructions

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Introduction

This example demonstrates how to use the RT-Thread ADC framework on the EtherKit to collect analog signals via ADC and perform digital signal conversion. The main content includes the following:

Hardware Description

As shown in the schematic above, the EtherKit provides an 8-channel analog input interface, which is connected to the MCU's ADC channels 0, 1, 2, and 3 for ADC0 and ADC1. (Note: The voltage range for the Analog Input is 0 to 1.8V.)

FSP Configuration Instructions

• Step 1: Open FSP and import the XML configuration file (or directly click the FSP link file in RT-Thread Studio).
• Step 2: Create a new r_adc stack, configure the ADC device, and select the channels to be used.

• Step 3: Save and click "Generate Project". The generated code will be saved in hal_data.c.

ENV Configuration

Use the env tool to enable ADC0 peripheral:

Example Code Description

The ADC source code is located in /projects/etherkit_driver_adc/src/hal_entry.c. The macros used are defined as follows:

The specific function is to sample the analog voltage from ADC0 channel 0 every 1000ms and perform a conversion. The code is as follows:

static int adc_vol_sample()
{
    rt_adc_device_t adc_dev;
    rt_uint32_t value, vol;
    rt_err_t ret = RT_EOK;
    /* Find the device */
    adc_dev = (rt_adc_device_t)rt_device_find(ADC_DEV_NAME);
    if (adc_dev == RT_NULL)
    {
        rt_kprintf("adc sample run failed! can't find %s device!\n", ADC_DEV_NAME);
        return RT_ERROR;
    }
    /* Enable the device */
    ret = rt_adc_enable(adc_dev, ADC_DEV_CHANNEL);
    /* Read the sampled value */
    value = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
    rt_kprintf("The value is :%d \n", value);
    /* Convert to corresponding voltage */
    vol = value * REFER_VOLTAGE / CONVERT_BITS;
    rt_kprintf("The voltage is :%d.%02d \n", vol / 100, vol % 100);
    /* Disable the channel */
    ret = rt_adc_disable(adc_dev, ADC_DEV_CHANNEL);
    return ret;
}

In the example, the while loop calls adc_vol_sample every 1000ms.

Compilation & Download

• RT-Thread Studio: In RT-Thread Studio’s package manager, download the EtherKit resource package, create a new project, and compile it.
• IAR: First, double-click mklinks.bat to create symbolic links between RT-Thread and the libraries folder. Then, use the Env tool to generate the IAR project. Finally, double-click project.eww to open the IAR project and compile it.

After compilation, connect the development board’s JLink interface to the PC and download the firmware to the development board.

Run Effect

The effect when using ADC0 channel 0 to sample a 1.8V voltage is shown below:

Notes

The ADC voltage input tolerance for the R9A07G084M08GBG chip is 1.8V.