大家好，

我用的Ch375芯片不知道為什么通電的時候然后發(fā)送復(fù)位命令（RESET_ALL），然后發(fā)送（CHECK_EXIST），不管發(fā)送什么數(shù)據(jù)，它返回的數(shù)據(jù)都為0xff。這是怎么回事？難道是我的CH375芯片壞了，還是我的代碼寫得有問題？

我用的是CH375S芯片，供電電壓為５V（這個芯片工作電壓是不是５V，還是3.3V？），微控制器為Microchip　PIC18F4550 工作頻率為４８MHz。電路我是按照CH375中文手冊上面的并口方式連接的。

以下是我用來讀寫CH375S芯片的代碼以及初始化的代碼：

//write command to CH375A void CH375A_CMD_Write(unsigned char cmd) { CH375_TRIS = 0x0; //make all pins as outputs CS = 0; //enable the chip RD = 1; A0 = 1; //command Delayus(2); //delay for 2us CH375_PORT_OUT = cmd; WR = 0; //write operation Delayus(2); //delay for 2us }

//Write data to CH375A void CH375A_DATA_Write(unsigned char data) { CH375_TRIS = 0x0; //make all pins as outputs CS = 0; //enable the chip RD = 1; //disables read operation A0 = 0; //data CH375_PORT_OUT = data; WR = 0; //enables write operation Delayus(2); //delay for 2us }

//Read data from CH375A unsigned char CH375A_DATA_Read(void) { unsigned char dat; CH375_TRIS = 0xff; //make all PortD pins as inputs CS = 0; //enable the chip RD = 0; //enables read operation WR = 1; //disables write operation A0 = 0; //data Delayus(2); //delay for 1us dat = CH375_PORT_IN; return dat; }

//Initialize CH375A unsigned char InitCH375A(void) { unsigned char i,status; CH375A_CMD_Write(CMD_RESET_ALL); //reset CH375A Delayms(100); //delay for bigger than 40ms CH375A_CMD_Write(CMD_CHECK_EXIST); CH375A_DATA_Write(0x55); status = CH375A_DATA_Read();

CH375A_CMD_Write(CMD_SET_USB_MODE); //set usb mode CH375A_DATA_Write(6); //set usb host, autogenerate SOF packet for (i=0xff; i > 0; i--) if(CH375A_DATA_Read() == CMD_RET_SUCCESS) break; if( i >0) return 0; //good else return 0xff; //error }

首先，測試數(shù)據(jù)返回0XFF就要檢查晶振起振沒有，還有就是復(fù)位完全不完全？接下來就是你的3個讀寫函數(shù)的時序上面有點問題，你用下面的讀寫程序試下看： void CH375A_CMD_Write(unsigned char cmd) { CH375_TRIS = 0x0; //make all pins as outputs Delayus(2); //delay for 2us CH375_PORT_OUT = cmd; A0 = 1; //command WR = 0; //write operation CS = 0; //enable the chip RD = 1; Delayus(2); //delay for 2us }

//Write data to CH375A void CH375A_DATA_Write(unsigned char data) { CH375_TRIS = 0x0; //make all pins as outputs、 Delayus(1); CH375_PORT_OUT = data; CS = 0; //enable the chip RD = 1; //disables read operation A0 = 0; //data WR = 0; //enables write operation Delayus(2); //delay for 2us }

//Read data from CH375A unsigned char CH375A_DATA_Read(void) { unsigned char dat; CH375_TRIS = 0xff; //make all PortD pins as inputs CS = 0; //enable the chip RD = 0; //enables read operation WR = 1; //disables write operation A0 = 0; //data Delayus(2); //delay for 1us dat = CH375_PORT_IN; CS = 1; //enable the chip RD = 1; //enables read operation return dat; }

多謝，我試試

我知道問題所在了，我把＃CS針接錯了，所以每次都輸出ff，但是還是不能通過測試狀態(tài)。我不管用什么數(shù)據(jù)測試（發(fā)送CHECK_EXIST命令）返回的數(shù)據(jù)都是0x5F，　讀寫的函數(shù)我已按照您說的改了。這是為什么？

為什么每次我用不同的數(shù)據(jù)來測試CH375（CHECK_EXIST）返回的總是0x5F呢？

我也檢查了硬件連接，好像是沒有什么問題，數(shù)據(jù)總線連接也沒有問題，請問hcn老大，什么原因能引起這個呢？

可能是你的數(shù)據(jù)口被鉗住了，你仔細(xì)檢查下你的硬件連線上面以及地址之類的有沒有沖突，以及在讀數(shù)據(jù)的時候有沒有其他的數(shù)據(jù)干擾

請問“數(shù)據(jù)口被鉗住了”是什么意思，我仔細(xì)檢查了硬件連線，沒有錯誤。地址我直接用代碼來表示，RESET_ALL＝05和CHECK_EXIST＝06。我自己又重新寫了一個小程序，就用來測試CH375芯片，但是還是通過不了CHECK_EXIST（06）。 這是我寫的程序 MCU為PIC18F452，晶振為16Mhz： #include #include

#pragma code

//define macros for CH375A #define A0 LATCbits.LATC3 #define RD LATCbits.LATC2 #define WR LATCbits.LATC1 #define CS LATCbits.LATC0 #define INT PORTBbits.RB0 #define CH375_PORT_IN PORTD #define CH375_PORT_OUT PORTD #define CH375_TRIS TRISD

void Delayus(unsigned char delay) { unsigned char i; for(i = 0; i < delay; i++) Nop(); Nop(); }

//delay for x ms void Delayms(unsigned char delay) { unsigned char i, j; while(delay-- != 0) { for(i=9; i!= 0; i--) { for(j=47;j !=0; j--) { Nop(); } } } }

void CH375A_CMD_Write(unsigned char cmd) { CH375_TRIS = 0x0; //make all pins as outputs Delayus(2); //delay for 2us CH375_PORT_OUT = cmd; A0 = 1; //command WR = 0; //write operation CS = 0; //enable the chip RD = 1; Delayus(2); //delay for 2us }

//Write data to CH375A void CH375A_DATA_Write(unsigned char data) { CH375_TRIS = 0x0; //make all pins as outputs、 Delayus(1); CH375_PORT_OUT = data; CS = 0; //enable the chip RD = 1; //disables read operation A0 = 0; //data WR = 0; //enables write operation Delayus(2); //delay for 2us }

//Read data from CH375A unsigned char CH375A_DATA_Read(void) { unsigned char dat; CH375_TRIS = 0xff; //make all PortD pins as inputs CS = 0; //enable the chip RD = 0; //enables read operation WR = 1; //disables write operation A0 = 0; //data Delayus(2); //delay for 1us dat = CH375_PORT_IN; CS = 1; //enable the chip RD = 1; //enables read operation return dat; }

//initialize the ports void InitPort(void) { LATA = 0; LATD = 0; LATC = 0; LATB = 0; TRISA=0xff; TRISB=0xff; TRISC=0x0; TRISD=0xff; TRISE=0xff; ADCON1 = 0x07; //make all ports digital I/O }

//Initialize CH375A unsigned char InitCH375A(void) { unsigned char i,status; CH375A_CMD_Write(0x05); //reset CH375A Delayms(50); //delay for bigger than 40ms CH375A_CMD_Write(0x06); CH375A_DATA_Write(0xff); status = CH375A_DATA_Read();

}

void main(void) { unsigned char status; InitPort(); Delayms(100); InitCH375A(); while(1); }

還有就是有沒有可能是晶振離CH375太遠(yuǎn)的原故？由于我這沒有SOP轉(zhuǎn)DIP的轉(zhuǎn)換器，而我只能把各個引腳用一些短鐵絲給焊上，然后插到實驗板上測試，有沒有可能在焊的時候因為引腳之間的距離太近了，所以產(chǎn)生干擾了，但是如果有干擾，為什么每一次的CHECK_EXIST返回值都是0x5F呢？如果我把它放到PCB上會不會解決問題？

這個不是主要的問題，我所說的總線被鉗住指的是你在操作的時候，將總線一直處于0X5F的狀態(tài)，而和你的硬件上面沒什么多大的問題

但是我也檢查過數(shù)據(jù)總線，當(dāng)我讓數(shù)據(jù)口為輸入狀態(tài)的時候，而CH375沒有被片選的時候，數(shù)據(jù)口輸入為0xFF，而當(dāng)片選打開的時候，我請求CHECK_EXIST命令，它返回的是0x5F，然后我馬上請求GET_STATUS，它返回的為0x20，這能不能說明數(shù)據(jù)總線沒被鉗??？

以下是我測試的主程序：

//Initialize CH375A unsigned char InitCH375A(void) { unsigned char i,status; CH375A_CMD_Write(0x05); //reset CH375A Delayms(50); //delay for bigger than 40ms CH375A_CMD_Write(0x06); CH375A_DATA_Write(0x55); status = CH375A_DATA_Read(); //status 返回 0x5F CH375A_CMD_Write(0x22); status = CH375A_DATA_Read(); //status 返回 0x20

}

hcn老大，

請問我還用不用連接RST和RST#這2個引腳，我現(xiàn)在的電路沒有連那2 個引腳。這是不是原因呢。還有今天我試了一下連接那2個引腳，把RST通過一個10K電阻接地，然后把RST#通過一個4.7K的電阻接5V，但是所有的返回都為0xff了，然后我把那2個引腳懸空，返回也還都是0xff了，這是怎么回事，是不是我把芯片燒了？

救命啊

這2個引腳是復(fù)位輸出腳，不需要連接的，正常復(fù)位的話，RST為低電平，RST#為高電平