In other words you dont understand how the protocol basically works...
thx FvM
I am using PIC16F877 and my compiler is MikroC for PIC and according your guidance I should fill all of the 512 bytes with "110" till have a successful operation ? meanwhile recently I found new problem, and it is related to CRC , the 7 last bites of command , you know, there is a formula in the datasheet for calculating the CRC :
I wrote this codes according a read program and expected to see on the LCD the written numbers on the SD but I just have 64 !!!! do you have any idea ?
// */ in This program PIC18f452 has comunicated with memory IC 25LC640
// */ and MCU save a 32 numbers (a page) in the 25LC640 through SPI
// */
char* text = "mikroElektronika";
unsigned x=0;
unsigned short take, buffer;
char txt[6];
char write_buf[512];
char read_buf[512];
unsigned int i;
unsigned long sector;
//////////////////////////////////////////6
char mmccommand(char cmd,unsigned long argument){
char r1;
char retry=0;
//send command
spi_write(cmd | 64);
spi_write(argument>>24);
spi_write(argument>>16);
spi_write(argument>>8);
spi_write(argument);
spi_write(149); //crc valid only for mmc_go_idle_state
//wait for response
//if more than 8 retries, card has timeout
//return the received 0xff
while(r1==255)
if(retry++>8) break;
return r1;
}
/////////////////////////////////////////////5
char mmcwrite(unsigned long sector, char* buffer ){
char r1;
unsigned i;
portd.f1=0;
//issue command
r1=mmccommand(24,sector<<9);
if(r1 != 0)
return r1;
spi_write(255); // send dummy
spi_write(254); //send data start token
for (i=0; i<512; i++) spi_write(*buffer++);
spi_write(255); // write 16-bit crc (dummy values)
spi_write(255);
r1 = Spi_Read(buffer); // read data response token
if((r1&35) != 5)
return r1;
while(!r1)
portd.f1=1; //CS
return 0; // return succes
}
/////////////////////////////////////////4
char mmcread(unsigned long sector, char* buffer ){
char r1;
unsigned i;
portd.f1=0;
r1= mmccommand(17,sector<<9);
if (r1!=0) return r1;
while(spi_read(buffer)!= 254)
for (i=0;i<512;i++) *buffer++ = spi_read(buffer);
spi_read(buffer); // read 16-bit CRC
spi_read(buffer);
portd.f1=1;
return 0;
}
/////////////////////////////////////////3
char mmcsendcommand(char cmd, unsigned long argument){
char r1;
portd.f1=0; //assert chip select
r1=mmccommand(cmd,argument); //issue the command
portd.f1=1;
return r1;
}
///////////////////////////////////////////// 2
char mmcreset(){
char i;
char retry;
char r1;
retry=0;
do{
for(i=0;i<10;i++) spi_write(255); // send dummy byte with CS high before accessing
r1= mmcsendcommand(0,0); //resetting card go to spi mode
retry++;
if(retry>10) return-1;
}while(r1 != 0x01);
retry=0;
do
{
r1= mmcsendcommand(1,0); // initializing card for operation
retry++;
if(retry>100)return-1;
}while(r1);
r1= mmcsendcommand(59,0); //turn off CRC checking to simplify communication
r1=mmcsendcommand(16,512);
return 0;
}
/////////////////////////////////////////////0
void main() {
trisd.f1=0;
portd.f1=1;
TRISB = 0; // PORTB is output
Lcd_Init(&PORTB); // Initialize LCD connected to PORTB
Lcd_Cmd(Lcd_CLEAR); // Clear display
Lcd_Cmd(Lcd_CURSOR_OFF); // Turn cursor off
Lcd_Out(1, 1, text); // Print text to LCD, 2nd row, 1st column
Spi_Init_Advanced(MASTER_OSC_DIV4,DATA_SAMPLE_End,CLK_IDLE_HIGH , HIGH_2_LOW) ;
mmcreset();
for (i=0;i<512;i++) write_buf[i]=i;
sector=5;
mmcwrite(sector,write_buf); // write to sector 5
delay_ms(1);
mmcread(sector,read_buf); // read of sector 5
while(1)
{
x=0;
while(x<512){
WordToStr(read_buf[x], txt);
Lcd_Out(2, 1, txt);
delay_ms(200);
Lcd_Cmd(Lcd_CLEAR);
Lcd_Out(1, 1, text);
portd.f1=1;
}
}
}//~!
According to the code, it's a timeout. One of the reset steps doesn't work as intended. This may be a hardware or software problem. Did you notice the requirement to start the initial SD card actions with a lower SPI frequency.
thanks your point for SPI was right and I changed it but still nothing meanwhile could you please have a quick look in the codes maybe find the errors. by the way , in the "mmcread ()" function what does mean ''*" in this line "char mmcread(unsigned long sector, char *buffer )" could you please explain clearly, and why it's using sector<<9 in this line r1= mmccommand(17,sector<<9); and one thing more what is the beneficial of this two line "spi_write(255); " in the "mmcwrite" function ? I mean why i should write 16-bit CRC (dummy values) ?
char* text = "mikroElektronika";
unsigned x=0;
unsigned short take, buffer;
char txt[6];
char write_buf[512];
char read_buf[512];
unsigned int i;
unsigned long sector;
//////////////////////////////////////////6
char mmccommand(char cmd,unsigned long argument){
char r1;
char retry=0;
//send command
spi_write(cmd | 64);
spi_write(argument>>24);
spi_write(argument>>16);
spi_write(argument>>8);
spi_write(argument);
spi_write(149); //crc valid only for mmc_go_idle_state
//wait for response
//if more than 8 retries, card has timeout
//return the received 0xff
//while(r1==255)
//if(retry++>8) break;
//return r1;
while (retry<8) {
r1=spi_read(buffer);
if (r1==255){
retry++;
if ( retry>8) break;
}
if (r1 !=255){
retry=9;
return r1;
}
}
}
/////////////////////////////////////////////5
char mmcwrite(unsigned long sector, char *buffer ){
char r1;
unsigned i;
portd.f1=0;
//issue command
r1=mmccommand(24,sector<<9);
if(r1 != 0)
return r1;
spi_write(255); // send dummy
spi_write(254); //send data start token
for (i=0; i<512; i++)
{ spi_write(*buffer++);
}
spi_write(255); // write 16-bit crc (dummy values)
spi_write(255);
r1 = Spi_Read(buffer); // read data response token
if((r1&31) != 5)
return r1;
while(!r1) portd.f1=1; //CS
return 0; // return succes
}
/////////////////////////////////////////4
char mmcread(unsigned long sector, char *buffer ){
char r1;
unsigned i;
portd.f1=0;
r1= mmccommand(17,sector<<9);
if (r1!=0) return r1;
while(spi_read(buffer)!= 254)
for (i=0;i<512;i++) *buffer++ = spi_read(buffer);
spi_read(buffer); // read 16-bit CRC
spi_read(buffer);
portd.f1=1;
return 0;
}
/////////////////////////////////////////3
char mmcsendcommand(char cmd, unsigned long argument){
char r1;
portd.f1=0; //assert chip select
r1=mmccommand(cmd,argument); //issue the command
portd.f1=1;
return r1;
}
///////////////////////////////////////////// 2
char mmcreset(){
char i;
char retry;
char r1;
retry=0;
do{
for(i=0;i<10;i++) spi_write(255); // send dummy byte with CS high before accessing
r1= mmcsendcommand(0,0); //resetting card go to spi mode
retry++;
if(retry>10) return-1;
}while(r1 != 1);
retry=0;
do
{
r1= mmcsendcommand(1,0); // initializing card for operation
retry++;
if(retry>100) return-1;
}while(r1);
r1= mmcsendcommand(59,0); //turn off CRC checking to simplify communication
r1=mmcsendcommand(16,512);
return 0;
}
/////////////////////////////////////////////0
void main() {
trisd.f1=0;
portd.f1=1;
TRISB = 0; // PORTB is output
Lcd_Init(&PORTB); // Initialize LCD connected to PORTB
Lcd_Cmd(Lcd_CLEAR); // Clear display
Lcd_Cmd(Lcd_CURSOR_OFF); // Turn cursor off
Lcd_Out(1, 1, text); // Print text to LCD, 2nd row, 1st column
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE, CLK_IDLE_LOW, LOW_2_HIGH);
mmcreset();
for (i=0;i<512;i++) {
write_buf[i]=i;
sector=5;
mmcwrite(sector,write_buf[i]); // write to sector 5
}
delay_ms(1);
mmcread(sector,read_buf[i]); // read of sector 5
while(1)
{
x=0;
while(x<512){
WordToStr(read_buf[x], txt);
Lcd_Out(2, 1, txt);
delay_ms(200);
Lcd_Cmd(Lcd_CLEAR);
Lcd_Out(1, 1, text);
portd.f1=1;
}
}
}//~!// */
char* text = "mikroElektronika";
unsigned x=110;
unsigned short take, buffer;
char txt[6];
char r2=1;
void Pins()
{
trisc.f2 =1;
portc.f2 = 0;
trisd.f1 =0;
portd.f1 =1;
trisd.f0 =0;
portd.f0 =0;
TRISB = 0;
}
//////////////////////////////////////////LCD
void lcd(){
Lcd_Cmd(Lcd_CLEAR); // Clear display
Lcd_Cmd(Lcd_CURSOR_OFF); // Turn cursor off
Lcd_Out(1, 1, text); // Print text to LCD, 2nd row, 1st column
WordToStr( x, txt);
Lcd_Out(2, 1, txt);
delay_ms(300);
Lcd_Cmd(Lcd_CLEAR);
Lcd_Out(1, 1, text);
}
//////////////////////////////////////////6
mmccommand(){
char r1=0;
char retry=0;
r2=1;
portd.f1=0;
spi_write(64);
spi_write(0);
spi_write(0);
spi_write(0);
spi_write(0);
spi_write(149); //crc valid only for mmc_go_idle_state
portd.f1=1;
delay_ms(3);
portd.f1=0;
r1=spi_read(buffer);
x=r1;
r1=0;
portd.f1=1;
lcd();
}
/////////////////////////////////////////////0
void main() {
// PORTB is output
Lcd_Init(&PORTB); // Initialize LCD connected to PORTB
Spi_Init_Advanced(MASTER_OSC_DIV16, DATA_SAMPLE_MIDDLE, CLK_IDLE_LOW, LOW_2_HIGH);
lcd();
pins();
mmccommand();
while(1){
}
}
//Yes, I was able to guess this myself. But you don't have the mikro C SD/MMC library?
That's a good way to start a project from the scratch. I would do it the same. The point is to check the results of each step exactly. I still think, that you can probably inherit existing code from the internet. But it's also very good to understand, how the stuff is working.
of curse it has but as I said I am trying to do it myself.
I tried this solution too, as you saw in my previous topic, but it didn't work !!! didn't see, any mistake in my last codes ? I think the problem refers to SPI but I don't know how should I solved it. by the way I set the SPI protocol as mikroc defaults but still nothings!!! I received these numbers as R1: 255,127,240,7 but I expected to receive 5 or at least 1