一个奇怪的1602液晶显示问题
我写了个1602的程序，完全可以驱动1602显示，但有一个这样的问题，我搞不明白。
主函数如下：
void main(void)
{
Initialize();//初始化液晶
WriteChar(5,1,'Q');//在第液晶第1行第6个位置会显示一个“A”
Delay(500);//延时500ms
WriteChar(5,2,'Q');//如果没有执行上面那条500ms延时的语句，在第液晶第2行第6个位置会显示一个“B”
//如果执行了上面那条500ms延时的语句，在第液晶第2行第6个位置不会有任何反应
//我试过，如果改为200ms的延时，是可以正常在第液晶第2行第6个位置会显示一个“B”的
while(1);
}
先谢谢大家了，这东西困扰我一天了，就是没想明白是什么原因。
[解决办法]
没有看懂你的意思，你说的A和B都是属于正常显示吗？你的程序里明明是Q……
另外，如果1602的显示不正常，大半是初始化的问题，另外还有一个就是延时设置问题
你这里只贴出了main函数，关键的initialize和writechar都没有贴出来，实在是无法分析什么
[解决办法]
//==============================================//// Filename: C8051f320_SMC1602A_Display.c //// //// Prozessor: C8051f320 //// Compiler: Keil C51 7.06 //// //// Author: Paul.Jia //// QQ: 79974439 //// Copyright: MKL PSC TSD ////==============================================////================================================//1. SYSCLK is unlimited here//2. Display by SMC1602A////Use 3 ports for control//Use 8 ports for data communications//And initialize them right in the Main ////Need ms delay function from the Main// extern void delay_ms(unsigned short ms);////Need initialize before use the diaplay function// void LCMInit(void);////Export these 2 function// void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData);// void DisplayListChar(unsigned char X, unsigned char Y, unsigned char *DData);//================================================//----------------------------// Include Files//----------------------------#include <c8051f320.h>#include <intrins.h>//----------------------------// Global Constants//----------------------------// Define control ports and data ports// P0.5 - digital push-pull (1602)RS// P0.6 - digital push-pull (1602)RW// P0.7 - digital push-pull (1602)E // P1.x - digital push-pull (1602)DATA// Have to initalize these ports in the Main//sbit RS1602 = P0 ^ 5; // Register select signal portsbit RW1602 = P0 ^ 6; // Data read/write portsbit E1602 = P0 ^ 7; // Enable signal port#define DATA1602 P1 // Data port// Define macro definition basic the selected ports//#define W_D_IN P1MDOUT &= 0x00 // Change Data port to open-drain#define W_D_OUT P1MDOUT |= 0xFF // Change Data port to push-pull// Define device busy flag//#define Busy 0x80//----------------------------// Function Prototypes//----------------------------// Write data to SMC1602A//void WriteDataLCM(unsigned char WDLCM);// Write command to SMC1602A//void WriteCommandLCM(unsigned char WCLCM, unsigned char BusyC);// Read data from SMC1602A//unsigned char ReadDataLCM(void);// Read command from SMC602A//unsigned char ReadStatusLCM(void);// Initalize SMC1602A//void LCMInit(void);// Display a char at the specified position//void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData);// Display a string at the specified position//void DisplayListChar(unsigned char X, unsigned char Y, unsigned char *DData);// Call a extern ms delay function//extern void delay_ms(unsigned short ms);//----------------------------// Subroutines//----------------------------//-----------------Write Data---------------------void WriteDataLCM(unsigned char WDLCM)//------------------------------------------------{ ReadStatusLCM(); // Detect Busy W_D_OUT; // Change Data port to push-pull DATA1602 = WDLCM; // Write data RS1602 = 1; // LCM_RS = 1; RW1602 = 0; // LCM_RW = 0; E1602 = 0; // LCM_E = 0; If SYSCLK is high, add a small delay into here delay_ms(4); E1602 = 1; // LCM_E = 1;}//----------------Write Command-------------------void WriteCommandLCM(unsigned char WCLCM, unsigned char BusyC)//------------------------------------------------{ if(BusyC) // Decide if detect Busy from parameter { ReadStatusLCM(); // Detect Busy } W_D_OUT; // Change Data port to push-pull DATA1602 = WCLCM; // Write command RS1602 = 0; // LCM_RS = 0; RW1602 = 0; // LCM_RW = 0; E1602 = 0; // LCM_E = 0; If SYSCLK is high, add a small delay into here delay_ms(4); E1602 = 1; // LCM_E = 1;}/*//------------------Read Data---------------------unsigned char ReadDataLCM(void)//------------------------------------------------{ RS1602 = 1; // LCM_RS = 1; RW1602 = 1; // LCM_RW = 1; E1602 = 0; // LCM_E = 0; If SYSCLK is high, add a small delay into here delay_ms(4); E1602 = 1; // LCM_E = 1; W_D_IN; // Change Data port to open-drain return DATA1602; // Return data}*///-----------------Read Command-------------------unsigned char ReadStatusLCM(void)//------------------------------------------------{ W_D_IN; // Change Data port to open-drain RS1602 = 0; // LCM_RS = 0; RW1602 = 1; // LCM_RW = 1; E1602 = 0; // LCM_E = 0; If SYSCLK is high, add a small delay into here delay_ms(4); E1602 = 1; // LCM_E = 1; while(DATA1602 & Busy); // Detect Busy return DATA1602; // Return data}//------------------Initalize---------------------void LCMInit(void)//------------------------------------------------{ DATA1602 = 0; WriteCommandLCM(0x38, 0); // Set display mode 3 times, no detect Busy delay_ms(5); WriteCommandLCM(0x38, 0); delay_ms(5); WriteCommandLCM(0x38, 0); delay_ms(5); // Keep above code WriteCommandLCM(0x38, 1); // Set display mode(8 bits, 2 rows, 5x7), begin detect Busy everytime WriteCommandLCM(0x08, 1); // Close display WriteCommandLCM(0x01, 1); // Clear screen WriteCommandLCM(0x06, 1); // Show the position of cursor move WriteCommandLCM(0x0C, 1); // Show boot-strap cursor setting WriteCommandLCM(0x80, 1); // The first position is row 1 line 1}//----------------Display one char----------------void DisplayOneChar(unsigned char X, unsigned char Y, unsigned char DData)//------------------------------------------------{ Y &= 0x1; X &= 0xF; // Revise X<=15 Y<=1 if(Y) // Add 0x40 to address for display row 2 { X |= 0x40; } X |= 0x80; // Count the address WriteCommandLCM(X, 0); // Send the address to SMC1602A WriteDataLCM(DData); // Write the char to SMC1602A}//----------------Display list char---------------void DisplayListChar(unsigned char X, unsigned char Y, unsigned char *DData)//------------------------------------------------{ unsigned char ListLength = 0; Y &= 0x1; X &= 0xF; // Revise X<=15 Y<=1 while(DData[ListLength] >= 0x20) // If the string end, quit { if(X <= 0xF) { DisplayOneChar(X, Y, DData[ListLength]); // Display one char ListLength++; X++; } }}
[解决办法]
不知道你用的是什么型号的1602，SMC1602A的要求是在初始化时，应有三次设置模式的操作就是我给的程序里的
WriteCommandLCM(0x38, 0); // Set display mode 3 times, no detect Busy
delay_ms(5);
WriteCommandLCM(0x38, 0);
delay_ms(5);
WriteCommandLCM(0x38, 0);
delay_ms(5);
这是Datasheet里明确要求的，你也可以注意一下你使用的1602，它的资料是怎么说的
另外你的write1602缺少读写检测，就是确保STA7=0的操作，这个也是按照SMC1602A的要求要有的，你可能需要看一下你的1602的相关要求
最后，在write1602里
P0 = Convert(a);
E = 1;
_nop_();
E = 0;
根据1602的要求，在写数据时E为高的时间应大于150ns，所以这里最好不要用_nop_();
[解决办法]
这样吧，你可以试一下，
在 WriteChar(5,1,'A');//在第液晶第1行第6个位置会显示一个“A”
之前增加一个 Delay(500);//延时500ms
来判断这个不正常的状况，是否有“WriteChar(5,1,'A'); ”
的影响因素