看你另外的一个帖子了，已经解决了。SPI，我们一般会约定一个数据格式为结束信号的，判断这个数据就可以吧。

能否提供一份TM4C129X 的 SPI从设备模式（slave spi mode）的代码，谢谢！

开的是主从的回环模式
//*****************************************************************************//// master_slave_loopback.c - Example demonstrating a simple I2C message//                           transmission and reception.//// Copyright (c) 2010-2014 Texas Instruments Incorporated.  All rights reserved.// Software License Agreement// //   Redistribution and use in source and binary forms, with or without//   modification, are permitted provided that the following conditions//   are met:// //   Redistributions of source code must retain the above copyright//   notice, this list of conditions and the following disclaimer.// //   Redistributions in binary form must reproduce the above copyright//   notice, this list of conditions and the following disclaimer in the//   documentation and/or other materials provided with the  //   distribution.// //   Neither the name of Texas Instruments Incorporated nor the names of//   its contributors may be used to endorse or promote products derived//   from this software without specific prior written permission.// // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.// // This is part of revision 2.1.0.12573 of the Tiva Firmware Development Package.////*****************************************************************************#include #include #include "inc/hw_i2c.h"#include "inc/hw_memmap.h"#include "inc/hw_types.h"#include "driverlib/gpio.h"#include "driverlib/i2c.h"#include "driverlib/pin_map.h"#include "driverlib/sysctl.h"#include "driverlib/uart.h"#include "utils/uartstdio.h"//*****************************************************************************////! addtogroup i2c_examples_list//!

I2C Master Loopback (i2c_master_slave_loopback)

//!//! This example shows how to configure the I2C0 module for loopback mode.//! This includes setting up the master and slave module.  Loopback mode//! internally connects the master and slave data and clock lines together.//! The address of the slave module is set in order to read data from the//! master.  Then the data is checked to make sure the received data matches//! the data that was transmitted.  This example uses a polling method for//! sending and receiving data.//!//! This example uses the following peripherals and I/O signals.  You must//! review these and change as needed for your own board://! - I2C0 peripheral//! - GPIO Port B peripheral (for I2C0 pins)//! - I2C0SCL - PB2//! - I2C0SDA - PB3//!//! The following UART signals are configured only for displaying console//! messages for this example.  These are not required for operation of I2C.//! - UART0 peripheral//! - GPIO Port A peripheral (for UART0 pins)//! - UART0RX - PA0//! - UART0TX - PA1//!//! This example uses the following interrupt handlers.  To use this example//! in your own application you must add these interrupt handlers to your//! vector table.//! - None.////*****************************************************************************//*****************************************************************************//// Number of I2C data packets to send.////*****************************************************************************#define NUM_I2C_DATA 3//*****************************************************************************//// Set the address for slave module. This is a 7-bit address sent in the// following format://                      [A6:A5:A4:A3:A2:A1:A0:RS]//// A zero in the "RS" position of the first byte means that the master// transmits (sends) data to the selected slave, and a one in this position// means that the master receives data from the slave.////*****************************************************************************#define SLAVE_ADDRESS 0x3C//*****************************************************************************//// This function sets up UART0 to be used for a console to display information// as the example is running.////*****************************************************************************voidInitConsole(void)[    //    // Enable GPIO port A which is used for UART0 pins.    // TODO: change this to whichever GPIO port you are using.    //    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);    //    // Configure the pin muxing for UART0 functions on port A0 and A1.    // This step is not necessary if your part does not support pin muxing.    // TODO: change this to select the port/pin you are using.    //    GPIOPinConfigure(GPIO_PA0_U0RX);    GPIOPinConfigure(GPIO_PA1_U0TX);    //    // Enable UART0 so that we can configure the clock.    //    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);    //    // Use the internal 16MHz oscillator as the UART clock source.    //    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);    //    // Select the alternate (UART) function for these pins.    // TODO: change this to select the port/pin you are using.    //    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);    //    // Initialize the UART for console I/O.    //    UARTStdioConfig(0, 115200, 16000000);]//*****************************************************************************//// Configure the I2C0 master and slave and connect them using loopback mode.////*****************************************************************************intmain(void)[    uint32_t pui32DataTx[NUM_I2C_DATA];    uint32_t pui32DataRx[NUM_I2C_DATA];    uint32_t ui32Index;    //    // Set the clocking to run directly from the external crystal/oscillator.    // TODO: The SYSCTL_XTAL_ value must be changed to match the value of the    // crystal on your board.    //    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |                   SYSCTL_XTAL_16MHZ);    //    // The I2C0 peripheral must be enabled before use.    //    SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);    //    // For this example I2C0 is used with PortB[3:2].  The actual port and    // pins used may be different on your part, consult the data sheet for    // more information.  GPIO port B needs to be enabled so these pins can    // be used.    // TODO: change this to whichever GPIO port you are using.    //    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);    //    // Configure the pin muxing for I2C0 functions on port B2 and B3.    // This step is not necessary if your part does not support pin muxing.    // TODO: change this to select the port/pin you are using.    //    GPIOPinConfigure(GPIO_PB2_I2C0SCL);    GPIOPinConfigure(GPIO_PB3_I2C0SDA);    //    // Select the I2C function for these pins.  This function will also    // configure the GPIO pins pins for I2C operation, setting them to    // open-drain operation with weak pull-ups.  Consult the data sheet    // to see which functions are allocated per pin.    // TODO: change this to select the port/pin you are using.    //    GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);    GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);    //    // Enable loopback mode.  Loopback mode is a built in feature that is    // useful for debugging I2C operations.  It internally connects the I2C    // master and slave terminals, which effectively let's you send data as    // a master and receive data as a slave.    // NOTE: For external I2C operation you will need to use external pullups    // that are stronger than the internal pullups.  Refer to the datasheet for    // more information.    //    HWREG(I2C0_BASE + I2C_O_MCR) |= 0x01;    //    // Enable and initialize the I2C0 master module.  Use the system clock for    // the I2C0 module.  The last parameter sets the I2C data transfer rate.    // If false the data rate is set to 100kbps and if true the data rate will    // be set to 400kbps.  For this example we will use a data rate of 100kbps.    //    I2CMasterInitExpClk(I2C0_BASE, SysCtlClockGet(), false);    //    // Enable the I2C0 slave module. This module is enabled only for testing    // purposes.  It does not need to be enabled for proper operation of the    // I2Cx master module.    //    I2CSlaveEnable(I2C0_BASE);    //    // Set the slave address to SLAVE_ADDRESS.  In loopback mode, it's an    // arbitrary 7-bit number (set in a macro above) that is sent to the    // I2CMasterSlaveAddrSet function.    //    I2CSlaveInit(I2C0_BASE, SLAVE_ADDRESS);    //    // Tell the master module what address it will place on the bus when    // communicating with the slave.  Set the address to SLAVE_ADDRESS    // (as set in the slave module).  The receive parameter is set to false    // which indicates the I2C Master is initiating a writes to the slave.  If    // true, that would indicate that the I2C Master is initiating reads from    // the slave.    //    I2CMasterSlaveAddrSet(I2C0_BASE, SLAVE_ADDRESS, false);    //    // Set up the serial console to use for displaying messages.  This is    // just for this example program and is not needed for I2C operation.    //    InitConsole();    //    // Display the example setup on the console.    //    UARTprintf("I2C Loopback Example ->");    UARTprintf("n   Module = I2C0");    UARTprintf("n   Mode = Single Send/Receive");    UARTprintf("n   Rate = 100kbpsnn");    //    // Initalize the data to send.    //    pui32DataTx[0] = 'I';    pui32DataTx[1] = '2';    pui32DataTx[2] = 'C';    //    // Initalize the receive buffer.    //    for(ui32Index = 0; ui32Index < NUM_I2C_DATA; ui32Index++)    [        pui32DataRx[ui32Index] = 0;    ]    //    // Indicate the direction of the data.    //    UARTprintf("Tranferring from: Master -> Slaven");    //    // Send 3 peices of I2C data from the master to the slave.    //    for(ui32Index = 0; ui32Index < NUM_I2C_DATA; ui32Index++)    [        //        // Display the data that the I2C0 master is transferring.        //        UARTprintf("  Sending: '%c'  . . .  ", pui32DataTx[ui32Index]);        //        // Place the data to be sent in the data register        //        I2CMasterDataPut(I2C0_BASE, pui32DataTx[ui32Index]);        //        // Initiate send of data from the master.  Since the loopback        // mode is enabled, the master and slave units are connected        // allowing us to receive the same data that we sent out.        //        I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_SEND);        //        // Wait until the slave has received and acknowledged the data.        //        while(!(I2CSlaveStatus(I2C0_BASE) & I2C_SLAVE_ACT_RREQ))        [        ]        //        // Read the data from the slave.        //        pui32DataRx[ui32Index] = I2CSlaveDataGet(I2C0_BASE);        //        // Wait until master module is done transferring.        //        while(I2CMasterBusy(I2C0_BASE))        [        ]        //        // Display the data that the slave has received.        //        UARTprintf("Received: '%c'n", pui32DataRx[ui32Index]);    ]    //    // Reset receive buffer.    //    for(ui32Index = 0; ui32Index < NUM_I2C_DATA; ui32Index++)    [        pui32DataRx[ui32Index] = 0;    ]    //    // Indicate the direction of the data.    //    UARTprintf("nnTranferring from: Slave -> Mastern");    //    // Modifiy the data direction to true, so that seeing the address will    // indicate that the I2C Master is initiating a read from the slave.    //    I2CMasterSlaveAddrSet(I2C0_BASE, SLAVE_ADDRESS, true);    //    // Do a dummy receive to make sure you don't get junk on the first receive.    //    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);    //    // Dummy acknowledge and wait for the receive request from the master.    // This is done to clear any flags that should not be set.    //    while(!(I2CSlaveStatus(I2C0_BASE) & I2C_SLAVE_ACT_TREQ))    [    ]    for(ui32Index = 0; ui32Index < NUM_I2C_DATA; ui32Index++)    [        //        // Display the data that I2C0 slave module is transferring.        //        UARTprintf("  Sending: '%c'  . . .  ", pui32DataTx[ui32Index]);        //        // Place the data to be sent in the data register        //        I2CSlaveDataPut(I2C0_BASE, pui32DataTx[ui32Index]);        //        // Tell the master to read data.        //        I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);        //        // Wait until the slave is done sending data.        //        while(!(I2CSlaveStatus(I2C0_BASE) & I2C_SLAVE_ACT_TREQ))        [        ]        //        // Read the data from the master.        //        pui32DataRx[ui32Index] = I2CMasterDataGet(I2C0_BASE);        //        // Display the data that the slave has received.        //        UARTprintf("Received: '%c'n", pui32DataRx[ui32Index]);    ]    //    // Tell the user that the test is done.    //    UARTprintf("nDone.nn");    //    // Return no errors    //    return(0);]