MSP430F5529LP SPI 通信测试
这次来测测SPI通信功能，最近买了个MAX7219驱动的LED点阵，恰好也是SPI通信，可以拿来测测。
SPI 通信
首先来看看开发板上引出的SPI接口。
其中完整的SPI接口是P3.0, P3.1 和 P3.2, 分别对应MOSI, MISO，CLK。 MAX7219 作为从设备，只需要接收控制信号，不需要输出数据到板子，所以使用三线制SPI，CS线可以是普通IO，为此我选择的三线SPI是：
P3.0 MOSI
P3.2 CLK
P6.4 CS/LOAD
USCI SPI 模式
UCSI 的 SPI 模式，其控制逻辑如下图所示，里面包含了时钟控制，波特率设定，数据收发，中断等所需的所有寄存器。后续使用寄存器编程可以参考此图。
MAX7219 LED 驱动器
接下来看看这个LED点阵屏啥样，8*8的LED单色点阵屏，下面带了个MAX7219 LED驱动器。除了可以驱动点阵屏，还可以驱动7段译码管。单位需要多本通信工程师职称证书挂资质，欢迎联系，陈工15007599549微同
这个点阵屏是可以级联的，通过SPI通信，引出5个线，3根控制线，剩下VCC，GND两根线. 对应板子的连线如下：
VCC --- 5V
GND --- GND
DIN --- P3.0
CS --- P6.4
CLK --- P3.2
驱动器包含一些8位寄存器，可以控制驱动器的输出，从而显示想要的点阵。
Digit0 - Digit7 对应8行的灯的输出信号，一个寄存器对应8个灯，上面表格的最右侧是寄存器的地址。给MAX7219 发送数据时，先发送寄存器地址，再发送数据。
Decode Mode 设置译码模式
Intensity 设置亮度等级（0x00 - 0x0F）
Scan limit 设置扫描限制，设置后可以只扫描一部分灯，对于点阵屏自然是全部扫描，所以设置为0x07 (参考手册)
Shutdown 使能功能，启用则可以点亮LED
Display Test 没试过，应该是用于测试，类似自检
测试
下面来测试下。代码如下，直接看注释，比较简单。
#include <msp430.h> #include <stdint.h> void spi_send(uint8_t address, uint8_t data);void init_MAX7219(void);// MAX7219 Register addresses #define MAX_NOOP 0x00 #define MAX_DIGIT0 0x01 #define MAX_DIGIT1 0x02 #define MAX_DIGIT2 0x03 #define MAX_DIGIT3 0x04 #define MAX_DIGIT4 0x05 #define MAX_DIGIT5 0x06 #define MAX_DIGIT6 0x07 #define MAX_DIGIT7 0x08 #define MAX_DECODEMODE 0x09 #define MAX_INTENSITY 0x0A #define MAX_SCANLIMIT 0x0B #define MAX_SHUTDOWN 0x0C #define MAX_DISPLAYTEST 0x0F // 8x8 number font const uint8_t number[][8] = { {0x3c, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3c}, // 0 {0x18, 0x38, 0x18, 0x18, 0x18, 0x18, 0x18, 0x3c}, // 1 {0x3c, 0x66, 0x06, 0x06, 0x0c, 0x18, 0x30, 0x7e}, // 2 {0x3c, 0x66, 0x06, 0x1e, 0x1e, 0x06, 0x66, 0x3c}, // 3 {0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18, 0x00}, // heart-full // {0x66, 0xDB, 0x81, 0x81, 0x42, 0x24, 0x18, 0x00}, // heart-empty // {0x00, 0x24, 0x7E, 0x7E, 0x3C, 0x18, 0x00, 0x00}, // small heart {0x00, 0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18}, // heart-full };const uint8_t iloveu[][8] = { {0x00, 0x7E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x7E}, // I {0x00, 0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18}, // love, heart-full {0x00, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x18}, // U };const uint8_t create_heart[10][2] = { // row, value {0, 0x00}, {2, 0x18}, {1, 0x24}, {1, 0x66}, {2, 0x99}, {3, 0x81}, {4, 0x81}, {5, 0x42}, {6, 0x24}, {7, 0x18},};uint8_t returnValue_SPI = 0x00;uint8_t row, framecounter;void clear_screen() { int row; for (row = 0; row < 8; row++) { spi_send(MAX_DIGIT0 + row, 0x00); } __delay_cycles(500000); // Wait a bit before showing next frame }int main(void){ WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer P6OUT |= BIT4; // Set P6.4 for CS P6DIR |= BIT4; // Set P6.4 to output direction P3SEL |= BIT0 + BIT2; // P3.0,2 option select //P3DIR |= BIT0+BIT1+BIT2; // Set P3.0,2 to output direction UCB0CTL1 |= UCSWRST; // **Put state machine in reset** UCB0CTL0 |= UCMST + UCCKPH + UCMSB + UCSYNC; // 3-pin, 8-bit SPI master // MSB UCB0CTL1 |= UCSSEL_2; // SMCLK UCB0BR0 = 0x02; // /2 UCB0BR1 = 0; // UCB0CTL1 &= ~UCSWRST; // Initialize USCI state machine __delay_cycles(100000); init_MAX7219(); __delay_cycles(1000); uint8_t row, framecounter; for (framecounter = 3; framecounter > 0; framecounter--) { // Load all 8 row/digit registers with data from number[framecounter] for (row = 0; row < 8; row++) { spi_send(MAX_DIGIT0 + row, number[framecounter][row]); } __delay_cycles(500000); // Wait a bit before showing next frame clear_screen(); } for (framecounter = 0; framecounter < 3; framecounter++) { // Load all 8 row/digit registers with data from number[framecounter] for (row = 0; row < 8; row++) { spi_send(MAX_DIGIT0 + row, iloveu[framecounter][row]); } __delay_cycles(500000); // Wait a bit before showing next frame clear_screen(); } for (framecounter = 0; framecounter < 10; framecounter++) { spi_send(MAX_DIGIT0 + create_heart[framecounter][0], create_heart[framecounter][1]); __delay_cycles(200000); // Wait a bit before showing next frame } while (1) { // Loop through some frames for (framecounter = 4; framecounter < 6; framecounter++) { // Load all 8 row/digit registers with data from number[framecounter] if (framecounter == 4) spi_send(MAX_INTENSITY, 0x07); else spi_send(MAX_INTENSITY, 0x02); for (row = 0; row < 8; row++) { spi_send(MAX_DIGIT0 + row, number[framecounter][row]); } __delay_cycles(400000); // Wait a bit before showing next frame } }}// Send 16 bits as: xxxxaaaadddddddd (ignore, address, data) // and use active low Chip Select void spi_send(uint8_t address, uint8_t data){ P6OUT &= ~BIT4; // CS low _delay_cycles(50); while (!(UCB0IFG & UCTXIFG)){} // Wait until done UCB0TXBUF = (address & 0x0F); while (!(UCB0IFG & UCTXIFG)){} // Wait until done UCB0TXBUF = (data); while (!(UCB0IFG & UCTXIFG)){} // Wait until done P6OUT |= BIT4; // CS high }void init_MAX7219(void){ // Initialise MAX7219 with 8x8 led matrix spi_send(MAX_NOOP, 0x00); // NO OP (seems needed after power on) spi_send(MAX_SCANLIMIT, 0x07); // Enable all digits (always needed for current/8 per row) spi_send(MAX_INTENSITY, 0x03); // Display intensity (0x00 to 0x0F) spi_send(MAX_DECODEMODE, 0); // No BCD decoding for led matrix // Clear all rows/digits spi_send(MAX_DIGIT0, 0); spi_send(MAX_DIGIT1, 0); spi_send(MAX_DIGIT2, 0); spi_send(MAX_DIGIT3, 0); spi_send(MAX_DIGIT4, 0); spi_send(MAX_DIGIT5, 0); spi_send(MAX_DIGIT6, 0); spi_send(MAX_DIGIT7, 0); spi_send(MAX_SHUTDOWN, 1); // Wake oscillators/display up }这个例子是显示I love U, love是个爱心桃，哈哈，给女朋友瞅瞅
串口控制LED输出
接下来再加点东西，把之前用的串口拿过来用用，通过串口控制LED的显示，不过这里要提到一个取模，上面实际上也用到了，取模软件比较多，就不推荐了。
针对MAX7219 驱动，github 上有很多的开源项目，其中就有一些字库，我参考的是
这是现成的字库，不过输出的方向和我的相差个90度，我就自个写了个C程序把它给旋转了。生成后放到font.h , 字库太长就不放了，下面是结合串口通信写的驱动程序。
#include <msp430.h> #include <stdint.h> #include <stdio.h> #include <string.h> #include "font.h" void spi_send(uint8_t address, uint8_t data);void init_MAX7219(void);// MAX7219 Register addresses #define MAX_NOOP 0x00 #define MAX_DIGIT0 0x01 #define MAX_DIGIT1 0x02 #define MAX_DIGIT2 0x03 #define MAX_DIGIT3 0x04 #define MAX_DIGIT4 0x05 #define MAX_DIGIT5 0x06 #define MAX_DIGIT6 0x07 #define MAX_DIGIT7 0x08 #define MAX_DECODEMODE 0x09 #define MAX_INTENSITY 0x0A #define MAX_SCANLIMIT 0x0B #define MAX_SHUTDOWN 0x0C #define MAX_DISPLAYTEST 0x0F // 8x8 number font const uint8_t number[][8] = {{0x3c, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3c}, // 0 {0x18, 0x38, 0x18, 0x18, 0x18, 0x18, 0x18, 0x3c}, // 1 {0x3c, 0x66, 0x06, 0x06, 0x0c, 0x18, 0x30, 0x7e}, // 2 {0x3c, 0x66, 0x06, 0x1e, 0x1e, 0x06, 0x66, 0x3c}, // 3 {0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18, 0x00}, // heart-full {0x00, 0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18}, // heart-full };const uint8_t iloveu[][8] = {{0x00, 0x7E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x7E}, // I {0x00, 0x66, 0xFF, 0xFF, 0xFF, 0x7E, 0x3C, 0x18}, // love, heart-full {0x00, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x18}, // U };const uint8_t create_heart[10][2] = {// row, value {0, 0x00},{2, 0x18},{1, 0x24},{1, 0x66},{2, 0x99},{3, 0x81},{4, 0x81},{5, 0x42},{6, 0x24},{7, 0x18},};void clear_screen() {int row;for (row = 0; row < 8; row++){spi_send(MAX_DIGIT0 + row, 0x00);}}// UART send char void send_char(char c){while (!(UCA1IFG&UCTXIFG)); // USCI_A1 TX buffer ready? UCA1TXBUF = c;}void send_strings(char *str){unsigned int i = 0;while(str != ' ') {send_char(str);i++;}}void flash_led(){uint8_t row, index;for (index = 3; index > 0; index--){// Load all 8 row/digit registers with data from number[index] for (row = 0; row < 8; row++){spi_send(MAX_DIGIT0 + row, number[index][row]);}__delay_cycles(500000); // Wait a bit before showing next frame clear_screen();}__delay_cycles(500000); // Wait a bit before showing next frame for (index = 0; index < 3; index++){// Load all 8 row/digit registers with data from number[index] for (row = 0; row < 8; row++){spi_send(MAX_DIGIT0 + row, iloveu[index][row]);}__delay_cycles(500000); // Wait a bit before showing next frame clear_screen();}__delay_cycles(500000); // Wait a bit before showing next frame for (index = 0; index < 10; index++){spi_send(MAX_DIGIT0 + create_heart[index][0], create_heart[index][1]);__delay_cycles(200000); // Wait a bit before showing next frame }__delay_cycles(500000); // Wait a bit before showing next frame int i = 0;while (i++ < 3){// Loop through some frames for (index = 4; index < 6; index++){// Load all 8 row/digit registers with data from number[index] if (index == 4)spi_send(MAX_INTENSITY, 0x07);else spi_send(MAX_INTENSITY, 0x02);for (row = 0; row < 8; row++){spi_send(MAX_DIGIT0 + row, number[index][row]);}__delay_cycles(400000); // Wait a bit before showing next frame }}}// Send 16 bits as: xxxxaaaadddddddd (ignore, address, data) // and use active low Chip Select void spi_send(uint8_t address, uint8_t data){P6OUT &= ~BIT4; // CS low _delay_cycles(50);while (!(UCB0IFG & UCTXIFG)){} // Wait until done UCB0TXBUF = (address & 0x0F);while (!(UCB0IFG & UCTXIFG)){} // Wait until done UCB0TXBUF = (data);while (!(UCB0IFG & UCTXIFG)){} // Wait until done P6OUT |= BIT4; // CS high }void init_MAX7219(void){// Initialise MAX7219 with 8x8 led matrix spi_send(MAX_NOOP, 0x00); // NO OP (seems needed after power on) spi_send(MAX_SCANLIMIT, 0x07); // Enable all digits (always needed for current/8 per row) spi_send(MAX_INTENSITY, 0x03); // Display intensity (0x00 to 0x0F) spi_send(MAX_DECODEMODE, 0); // No BCD decoding for led matrix // Clear all rows/digits spi_send(MAX_DIGIT0, 0);spi_send(MAX_DIGIT1, 0);spi_send(MAX_DIGIT2, 0);spi_send(MAX_DIGIT3, 0);spi_send(MAX_DIGIT4, 0);spi_send(MAX_DIGIT5, 0);spi_send(MAX_DIGIT6, 0);spi_send(MAX_DIGIT7, 0);spi_send(MAX_SHUTDOWN, 1); // Wake oscillators/display up }void show_char(uint8_t ch){uint8_t row;clear_screen();// Load all 8 row/digit registers with data from ASCII_FONTS[ch] for (row = 0; row < 8; row++){spi_send(MAX_DIGIT0 + row, ASCII_FONTS[ch][row]);}}uint8_t chr = 0;int main(void){WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer // USCI_A1 UART P4SEL |= BIT4+BIT5; // P4.4,5 = USCI_A1 TXD/RXD UCA1CTL1 |= UCSWRST; // **Put state machine in reset** UCA1CTL1 |= UCSSEL_2; // SMCLK UCA1BR0 = 9; // 1MHz 115200 (see User's Guide) UCA1BR1 = 0; // 1MHz 115200 UCA1MCTL |= UCBRS_1 + UCBRF_0; // Modulation UCBRSx=1, UCBRFx=0 UCA1CTL1 &= ~UCSWRST; // **Initialize USCI state machine** UCA1IE |= UCRXIE; // Enable USCI_A1 RX interrupt // MAX7219 SPI P6OUT |= BIT4; // Set P6.4 for CS P6DIR |= BIT4; // Set P6.4 to output direction P3SEL |= BIT0 + BIT2; // P3.0,2 option select //P3DIR |= BIT0+BIT1+BIT2; // Set P3.0,2 to output direction UCB0CTL1 |= UCSWRST; // **Put state machine in reset** UCB0CTL0 |= UCMST + UCCKPH + UCMSB + UCSYNC; // 3-pin, 8-bit SPI master // MSB UCB0CTL1 |= UCSSEL_2; // SMCLK UCB0BR0 = 0x02; // /2 UCB0BR1 = 0; // UCB0CTL1 &= ~UCSWRST; // Initialize USCI state machine __delay_cycles(100000);__bis_SR_register( GIE); // interrupts enabled init_MAX7219();__delay_cycles(1000);flash_led();uint8_t old_chr = 0;while(1) {// __bis_SR_register(LPM0_bits); if (old_chr != chr) {show_char(chr);old_chr = chr;}__delay_cycles(1000);}}// Echo back RXed character, confirm TX buffer is ready first #if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__) #pragma vector=USCI_A1_VECTOR __interrupt void USCI_A1_ISR(void)#elif defined(__GNUC__) void __attribute__ ((interrupt(USCI_A1_VECTOR))) USCI_A1_ISR (void)#else #error Compiler not supported! #endif {switch(__even_in_range(UCA1IV,4)){case 0:break; // Vector 0 - no interrupt case 2: // Vector 2 - RXIFG while (!(UCA1IFG&UCTXIFG)); // USCI_A1 TX buffer ready? chr = UCA1RXBUF;UCA1TXBUF = chr; // TX -> RXed character // __bic_SR_register_on_exit(LPM0_bits); break;case 4:break; // Vector 4 - TXIFG default: break;}}
在UART中断中把接收到的字符存在buf中，主循环去判断是否有更新，如果有就驱动LED更新显示。
比如，咱显示个大写字母Q
哈哈，是不是很有趣，其实可以搞些好玩的动画，横屏或者竖屏滚动，或者旋转，然后配合时间控制以及亮度调节，会更好玩。时间有限就先这样吧。
参考资料
MAX7219-MAX7221_cn.pdf (1.35 MB, 下载次数: 0)
此帖出自微控制器 MCU论坛
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