[参考译文] LP-MSPM0G3507：16x2 LCD 字符显示问题

我发现了这个问题、它与命令的时序有关。
我随附了更新后的代码。

/*
 * Copyright (c) 2020, Texas Instruments Incorporated
 * All rights reserved.
 *
 * 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.
 */

#include "ti/devices/msp/m0p/mspm0g350x.h"
#include "ti/driverlib/m0p/dl_core.h"
#include "ti/driverlib/m0p/dl_systick.h"
#include "ti_msp_dl_config.h"
#include <machine/_stdint.h>
#include <sys/_stdint.h>

/* Pin definitions (customize based on your hardware) */
#define RS_PIN GPIO_GRP_0_RS_PIN    // Example: Port 1, Pin 0
#define ENABLE_PIN GPIO_GRP_0_E_PIN // Example: Port 1, Pin 1
#define D4_PIN GPIO_GRP_0_D4_PIN    // Example: Port 1, Pin 2
#define D5_PIN GPIO_GRP_0_D5_PIN    // Example: Port 1, Pin 3
#define D6_PIN GPIO_GRP_0_D6_PIN    // Example: Port 1, Pin 4
#define D7_PIN GPIO_GRP_0_D7_PIN    // Example: Port 1, Pin 5

#define HIGH 1
#define LOW 0

#define LCD_PORT GPIO_GRP_0_PORT // Example: GPIO Port A

#define MAX_TICKS 0xFFFFFF // Maximum ticks for SysTick (24-bit)

/* Function prototypes */
void delayMiliseconds(uint32_t milliseconds);
void delayMicroseconds(uint32_t microseconds);
void digitalWrite(uint32_t pins, uint8_t state);

// Function prototypes
void LCD_Command(unsigned char cmd);
void LCD_Data(unsigned char data);
void LCD_Init(void);
void LCD_String(char *str);
void LCD_Clear();

int main(void) {
  SYSCFG_DL_init();
  LCD_Init();

  while (1) {
    DL_GPIO_togglePins(GPIO_GRP_1_PORT, GPIO_GRP_1_PIN_0_PIN);
    delayMiliseconds(3000);
    LCD_String("Hello Abhinav");
    delayMiliseconds(3000);
    LCD_Clear();
  }
}

void delayMiliseconds(uint32_t milliseconds) {
  uint32_t ticks_per_ms = CPUCLK_FREQ / 1000;
  uint32_t max_delay_ms = MAX_TICKS / ticks_per_ms;

  while (milliseconds > 0) {
    uint32_t delayMiliseconds =
        (milliseconds > max_delay_ms) ? max_delay_ms : milliseconds;
    uint32_t ticks = delayMiliseconds * ticks_per_ms;

    DL_SYSTICK_init(ticks);
    DL_SYSTICK_enable();

    // Wait until the COUNTFLAG is set
    while ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) == 0)
      ;

    DL_SYSTICK_disable();

    milliseconds -= delayMiliseconds;
  }
}

void delayMicroseconds(uint32_t microseconds) {

  uint32_t ticks = microseconds * (CPUCLK_FREQ / 1000000);

  // Ensure the reload value is within 24-bit range
  if (ticks > 0xFFFFFF)
    ticks = 0xFFFFFF;

  DL_SYSTICK_init(ticks);

  // Start SysTick
  DL_SYSTICK_enable();

  // Wait until the COUNTFLAG is set
  while ((SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk) == 0)
    ;

  // Stop SysTick
  DL_SYSTICK_disable();
}

void digitalWrite(uint32_t pins, uint8_t state) {
  if (state == HIGH) {
    DL_GPIO_setPins(LCD_PORT, pins);
  } else if (state == LOW) {
    DL_GPIO_clearPins(LCD_PORT, pins);
  } else {
  }
}

void LCD_Command(unsigned char cmd) {
  // Send the higher nibble
  digitalWrite(D4_PIN, (cmd & 0x10) >> 4);
  delayMicroseconds(1);
  digitalWrite(D5_PIN, (cmd & 0x20) >> 5);
  delayMicroseconds(1);
  digitalWrite(D6_PIN, (cmd & 0x40) >> 6);
  delayMicroseconds(1);
  digitalWrite(D7_PIN, (cmd & 0x80) >> 7);
  delayMicroseconds(1);
  digitalWrite(RS_PIN, LOW); // Command mode
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, HIGH);
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, LOW);
  delayMicroseconds(1);

  // Send the lower nibble
  digitalWrite(D4_PIN, cmd & 0x01);
  delayMicroseconds(1);
  digitalWrite(D5_PIN, (cmd & 0x02) >> 1);
  delayMicroseconds(1);
  digitalWrite(D6_PIN, (cmd & 0x04) >> 2);
  delayMicroseconds(1);
  digitalWrite(D7_PIN, (cmd & 0x08) >> 3);
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, HIGH);
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, LOW);
  delayMicroseconds(30);
}

void LCD_Data(unsigned char data) {
  // Send the higher nibble
  digitalWrite(D4_PIN, (data & 0x10) >> 4);
  delayMicroseconds(1);
  digitalWrite(D5_PIN, (data & 0x20) >> 5);
  delayMicroseconds(1);
  digitalWrite(D6_PIN, (data & 0x40) >> 6);
  delayMicroseconds(1);
  digitalWrite(D7_PIN, (data & 0x80) >> 7);
  delayMicroseconds(1);

  digitalWrite(RS_PIN, HIGH); // Data mode
  digitalWrite(ENABLE_PIN, HIGH);
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, LOW);
  delayMicroseconds(1);

  // Send the lower nibble
  digitalWrite(D4_PIN, data & 0x01);
  delayMicroseconds(1);
  digitalWrite(D5_PIN, (data & 0x02) >> 1);
  delayMicroseconds(1);
  digitalWrite(D6_PIN, (data & 0x04) >> 2);
  delayMicroseconds(1);
  digitalWrite(D7_PIN, (data & 0x08) >> 3);
  delayMicroseconds(1);

  digitalWrite(ENABLE_PIN, HIGH);
  delayMicroseconds(1);
  digitalWrite(ENABLE_PIN, LOW);
  delayMicroseconds(30);
}

void LCD_Init(void) {
  delayMiliseconds(50);
  digitalWrite(RS_PIN, LOW);     // RS = 0
  digitalWrite(ENABLE_PIN, LOW); // EN = 0
  // Initialize LCD in 4-bit mode
  LCD_Command(0x02); // Function set: Initialize
  LCD_Command(0x28); // Function set: 4-bit mode
  LCD_Command(0x01); // 2-line display, 5x8 dots
  LCD_Command(0x0c); // Display ON, Cursor OFF, Blink OFF
  LCD_Command(0x06); // Entry mode: Increment cursor

  delayMiliseconds(2);
  LCD_Command(0x80); /* Cursor 1st row 0th position */
}

void LCD_String(char *str) {
  while (*str) {
    LCD_Data(*str++);
  }
}

void LCD_Clear() {
  LCD_Command(0x01); /*clear display screen*/
  delayMiliseconds(3);
}