Microchip PIC18F8722与4D系统uLCD-70-DT的串行通信

我正在做一个项目，使用4D系统gen4 uLCD-70dt和PIC18F8722来控制机器。这两个设备使用一对MAX232串行驱动程序链接

我以前曾使用PIC18F4520进行过此设置的试验，串行通信没有问题。现在，当PIC向显示器发送轮询请求时，显示器会做出响应，但PIC不会收到数据。 代码id非常简单（用于测试），我使用示波器检查了PIC引脚上的数据流（RX和TX），信号看起来很好。（电压和波特率检查）

我确实使用了一个GenieSerial.h，它是为我在网上找到的18F4520构建的，并为18f8722进行了修改。（此处可能出现错误）

我猜我的配置位或EUSART设置位有错误，但我一生都找不到

谢谢你的帮助

主要代码：

   /*
   * File:   trial1.c
   * Author: Steve
   *
   * Created on May 2, 2017, 3:06 PM
   */

// PIC18F8722 Configuration Bit Settings

// 'C' source line config statements

// CONFIG1H
#pragma config OSC = HS         // Oscillator Selection bits (External RC       oscillator, CLKO function on RA6)
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF       // Internal/External Oscillator Switchover bit (Two-Speed Start-up disabled)

// CONFIG2L
#pragma config PWRT = OFF       // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = SBORDIS  // Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only (SBOREN is disabled))
#pragma config BORV = 3         // Brown-out Voltage bits (Minimum setting)

// CONFIG2H
#pragma config WDT = OFF        // Watchdog Timer (WDT disabled (control is placed on the SWDTEN bit))
#pragma config WDTPS = 32768    // Watchdog Timer Postscale Select bits (1:32768)

// CONFIG3L
#pragma config MODE = MC        // Processor Data Memory Mode Select bits (Microcontroller mode)
#pragma config ADDRBW = ADDR20BIT// Address Bus Width Select bits (20-bit Address Bus)
#pragma config DATABW = DATA16BIT// Data Bus Width Select bit (16-bit External Bus mode)
#pragma config WAIT = OFF       // External Bus Data Wait Enable bit (Wait selections are unavailable for table reads and table writes)

 // CONFIG3H
#pragma config CCP2MX = PORTC   // CCP2 MUX bit (ECCP2 input/output is multiplexed with RC1)
#pragma config ECCPMX = PORTE   // ECCP MUX bit (ECCP1/3 (P1B/P1C/P3B/P3C) are multiplexed onto RE6, RE5, RE4 and RE3 respectively)
#pragma config LPT1OSC = OFF    // Low-Power Timer1 Oscillator Enable bit (Timer1 configured for higher power operation)
#pragma config MCLRE = ON       // MCLR Pin Enable bit (MCLR pin enabled; RG5 input pin disabled)

// CONFIG4L
#pragma config STVREN = ON      // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config LVP = ON         // Single-Supply ICSP Enable bit (Single-Supply ICSP enabled)
#pragma config BBSIZ = BB2K     // Boot Block Size Select bits (1K word (2 Kbytes) Boot Block size)
#pragma config XINST = OFF      // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))

// CONFIG5L
#pragma config CP0 = OFF        // Code Protection bit Block 0 (Block 0 (000800, 001000 or 002000-003FFFh) not code-protected)
#pragma config CP1 = OFF        // Code Protection bit Block 1 (Block 1 (004000-007FFFh) not code-protected)
#pragma config CP2 = OFF        // Code Protection bit Block 2 (Block 2 (008000-00BFFFh) not code-protected)
#pragma config CP3 = OFF        // Code Protection bit Block 3 (Block 3 (00C000-00FFFFh) not code-protected)
#pragma config CP4 = OFF        // Code Protection bit Block 4 (Block 4 (010000-013FFFh) not code-protected)
#pragma config CP5 = OFF        // Code Protection bit Block 5 (Block 5 (014000-017FFFh) not code-protected)
#pragma config CP6 = OFF        // Code Protection bit Block 6 (Block 6 (01BFFF-018000h) not code-protected)
#pragma config CP7 = OFF        // Code Protection bit Block 7 (Block 7 (01C000-01FFFFh) not code-protected)

// CONFIG5H
#pragma config CPB = OFF        // Boot Block Code Protection bit (Boot Block (000000-0007FFh) not code-protected)
#pragma config CPD = OFF        // Data EEPROM Code Protection bit (Data EEPROM not code-protected)

// CONFIG6L
#pragma config WRT0 = OFF       // Write Protection bit Block 0 (Block 0 (000800, 001000 or 002000-003FFFh) not write-protected)
#pragma config WRT1 = OFF       // Write Protection bit Block 1 (Block 1 (004000-007FFFh) not write-protected)
#pragma config WRT2 = OFF       // Write Protection bit Block 2 (Block 2 (008000-00BFFFh) not write-protected)
#pragma config WRT3 = OFF       // Write Protection bit Block 3 (Block 3 (00C000-00FFFFh) not write-protected)
#pragma config WRT4 = OFF       // Write Protection bit Block 4 (Block 4 (010000-013FFFh) not write-protected)
#pragma config WRT5 = OFF       // Write Protection bit Block 5 (Block 5 (014000-017FFFh) not write-protected)
#pragma config WRT6 = OFF       // Write Protection bit Block 6 (Block 6 (01BFFF-018000h) not write-protected)
#pragma config WRT7 = OFF       // Write Protection bit Block 7 (Block 7 (01C000-01FFFFh) not write-protected)

// CONFIG6H
#pragma config WRTC = OFF       // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)
#pragma config WRTB = OFF       // Boot Block Write Protection bit (Boot Block (000000-007FFF, 000FFF or 001FFFh) not write-protected)
#pragma config WRTD = OFF       // Data EEPROM Write Protection bit (Data EEPROM not write-protected)

// CONFIG7L
#pragma config EBTR0 = OFF      // Table Read Protection bit Block 0 (Block 0 (000800, 001000 or 002000-003FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF      // Table Read Protection bit Block 1 (Block 1 (004000-007FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF      // Table Read Protection bit Block 2 (Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF      // Table Read Protection bit Block 3 (Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks)
#pragma config EBTR4 = OFF      // Table Read Protection bit Block 4 (Block 4 (010000-013FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR5 = OFF      // Table Read Protection bit Block 5 (Block 5 (014000-017FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR6 = OFF      // Table Read Protection bit Block 6 (Block 6 (018000-01BFFFh) not protected from table reads executed in other blocks)
#pragma config EBTR7 = OFF      // Table Read Protection bit Block 7 (Block 7 (01C000-01FFFFh) not protected from table reads executed in other blocks)

// CONFIG7H
#pragma config EBTRB = OFF      // Boot Block Table Read Protection bit (Boot Block (000000-007FFF, 000FFF or 001FFFh) not protected from table reads executed in other blocks)

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#include <xc.h>
#include "GenieSerial.h"
#define _XTAL_FREQ 20000000


// MAIN PROGRAM LOOP

void main()
{
    unsigned char incoming=37;

    usart();

    while(1)
    {


        incoming = genieread(0x04,0x00);        //read slider 0
        __delay_ms(104);
        geniewrite_coolgauge(0x00, incoming);    //send data back to display here
         __delay_ms(104);

    }
}`

---

当没有中断处理程序时，GenieSerial.h同时启用发送和接收中断。如果中断标志没有正确重置，这可能会导致问题。我会先禁用中断，看看这是否会清除它：

PIE1bits.TXIE  = 0;
PIE1bits.RC1IE = 0;

因为它只使用轮询来处理串行端口，所以最好禁用中断

---

还要确保振荡器以预期频率运行。根据数据表，串行端口以9766波特运行。确保这不会导致任何问题。您可以使用20MHz的备用设置，BRGH=1和SPBRG=129将速度设置为9615波特，这更接近9600波特的规格。请参阅数据表（39646c.pdf）中的第253页。

如果将pic的串行端口连接到rs232-to-usb适配器，会发生什么情况？终端客户端是否显示预期数据？当你发送pic数据时，它会收到吗？

PIE1bits.TXIE  = 0;
PIE1bits.RC1IE = 0;