Adapter One-Wire Mode

This sample code guide is designed to help users easily and comprehensively understand UART sample. This sample code demonstrates how adapter one-wire works. When the adapter plugs in, it works as UART RX. When the adapter plugs out, it works as GPIO.

Requirements

For hardware requirements, please refer to the Requirements.

In addition, it is necessary to install serial port assistant tools such as PuTTY or UartAssist on the PC terminal.

Wiring

On EVB, TX of FT232 is connected to VADP.

• RTL87x3E: On EVB, the capacitance of ADPIN on PCB needs to be replaced by 100pF.

• RTL87x3D: The daughter board changes C186 to 100pf. The motherboard removes C164, DP38 and C71, and raises VAUX1 to 3.3V, connecting VIO4 to VAUX1.

The hardware connection of UART sample code is shown in the figure below.

UART Sample Code Hardware Connection Diagram

Configurations

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

adp_1wire_uart_demo();

Building and Downloading

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

Experimental Verification

Preparation Phase

Start a PC terminal program like PuTTY or UartAssist and connect to the used COM port with the following UART settings:

• Baud rate: 9600.

• 8 data bits.

• 1 stop bit.

• No parity.

• No hardware flow control.

Testing Phase

1. Press the Reset button on the EVB.

2. Connect TX of FT232 and VADP, the following log will be displayed in Debug Analyze, and chip can receive uart data from PC terminal. Use PC terminal program to send data to chip, the chip will print the received data in Debug Analyzer.

   adp_io_in_out: adp io in
   

3. Disconnect TX of FT232 and VADP, the following log will be displayed in Debug Analyze.

   adp_io_in_out: adp io out
   

Code Overview

This section introduces the code and process description for initialization and corresponding function implementation in the sample.

Source Code Directory

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

• Source code directory: sdk\src\sample\io_demo\adp_1wire\adp_1wire_uart_demo.c.

Initialization

1. Call adp_set_debounce_time() to set ADP IO function debounce time.

2. Call adp_register_state_change_cb() to register ADP IO callback.

Functional Implementation

ADP IO Callback Handle

1. If ADP plug in, close ADP function and initialize UART, UART initialization flow is shown in the following figure:

   1. Call adp_close() to close ADP function.

   2. Call UART_DeInit() to deinitialize the UART peripheral registers to their default reset values.

   3. Call Pad_Config() and Pinmux_Config() to initialize the pin.

   Pad_Config(ADP_PIN, PAD_PINMUX_MODE, PAD_IS_PWRON, PAD_PULL_NONE, PAD_OUT_DISABLE, PAD_OUT_LOW);
   Pinmux_Config(ADP_PIN, UART0_RX);
   

   4. Call RCC_PeriphClockCmd() to enable the UART clock and function.

   5. Initialize the UART peripheral:

      1. Define the UART_InitTypeDef type uartInitStruct, and call UART_StructInit() to pre-fill uartInitStruct with default values.

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

      3. Call UART_Init() to initialize the UART peripheral.

   UART Initialization Parameters

   UART Hardware Parameters	Setting in the uartInitStruct	UART
   div	UART_InitTypeDef::div	271
   ovsr	UART_InitTypeDef::ovsr	10
   ovsr_adj	UART_InitTypeDef::ovsr_adj	0x24A
   Parity Check	UART_InitTypeDef::parity	UART_PARITY_NO_PARTY
   Stop Bit	UART_InitTypeDef::stopBits	UART_STOP_BITS_1
   Data Format	UART_InitTypeDef::wordLen	UART_WROD_LENGTH_8BIT
   Hardware Flow Control	UART_InitTypeDef::autoFlowCtrl	UART_AUTO_FLOW_CTRL_DIS
   RX Trigger Level	UART_InitTypeDef::rxTriggerLevel	UART_RX_FIFO_TRIGGER_LEVEL_14BYTE

   6. Call UART_INTConfig() to enable received data available interrupt UART_INT_RD_AVA and RX idle timeout interrupt UART_INT_IDLE and receiver line status interrupt UART_INT_LINE_STS.

   7. Call NVIC_Init() to enable NVIC of UART.

2. If ADP plug out, print the following log.

   adp_io_in_out: adp io out
   

UART Initialization Flow Chart

Interrupt Handle

After the PC terminal sends a string, the chip will trigger UART interrupts. UART interrupt handle flow is shown in the following figure.

UART Interrupt Handle Flow

1. Call UART_GetIID() to get the interrupt ID.

2. If the RX FIFO level reached the RX trigger level set in UART_InitTypeDef::rxTriggerLevel, UART_INT_ID_RX_LEVEL_REACH interrupt first is triggered first:

   1. Call UART_GetRxFIFOLen() to get the data length in RX FIFO.

   2. Call UART_ReceiveData() to receive data from RX FIFO.

3. There’s at least 1 UART data in the RX FIFO but no character has been input to the RX FIFO or read from it for the last time of 4 characters. UART_INT_ID_RX_TMEOUT interrupt is triggered:

   1. Call UART_GetRxFIFOLen() to get the data length in RX FIFO.

   2. Call UART_ReceiveData() to receive data from RX FIFO.

4. If No data is received in RX idle timeout time after the RX FIFO is empty (data is received before), the UART_FLAG_RX_IDLE interrupt is triggered:

   1. Call UART_GetFlagState() to check UART_FLAG_RX_IDLE interrupt flag state.

   2. Call UART_INTConfig() to disable UART_INT_IDLE interrupt.

   3. Call UART_INTConfig() to enable UART_INT_IDLE interrupt.

5. When parity error or frame error or break error or overrun error occurs, UART_INT_ID_LINE_STATUS interrupt is triggered:

   1. Call UART_GetLineStatus() to get line status.

   2. If break error occurs:

      1. Call UART_INTConfig() to disable RX idle timeout interrupt UART_INT_IDLE.

      2. Call UART_INTConfig() to disable received data available interrupt UART_INT_RD_AVA.

      3. Call UART_INTConfig() to disable receiver line status interrupt UART_INT_LINE_STS.

      4. Call adp_open() to open ADP function.