TM4C1294NCPDT: SPI Flash Read & Write

Hi,

  I don't understand what your log means. Who prints these logs? Are you using some custom SPI Flash library? Where did you get the library from? 

Hi,
     I am using FreeRTOS for the TM4C129 MCU.I used the #include "driverlib/ssi.h", no other custom library been used. I am trying to write and read data in the  MX25L51245G flash chip. So the logs were read via UART which I shared you above. I could able to write the data by the command MX25_CMD_WREN  (0x06). Facing issue on reading data. 

Can you share your code?

I'm still not clear how you are writing and reading the SPI flash and how you output the logs via UART. 

What is MX25_CMD_WREN? How would I know what this function is doing? This must be your own function, certainly not a TivaWare SDK function. 

Yes, Here with the "driverlib/ssi.h", created function for flash write which mentioned below, 

 From the below function,facing issue on reading data. Also, the logs which I mentioned is read from SPI chip and stored in log_buffer. 

void EEPROM_ReadAllData(uint32_t start_address, uint32_t max_length)
{
char read_buffer[PAGE_SIZE] = {0};
char line_buffer[PAGE_SIZE] = {0};
uint32_t current_address = start_address;
uint32_t bytes_read = 0;
uint32_t line_index = 0;

while (bytes_read < max_length)
{
// Read a page of data
memset(read_buffer, 0, PAGE_SIZE);
EEPROM_Read(current_address / PAGE_SIZE, read_buffer, PAGE_SIZE);
int i;
// Process the read buffer line by line
for (i = 0; i < PAGE_SIZE; i++)
{
if (read_buffer[i] == '\0' || read_buffer[i] == '\r' || read_buffer[i] == '\n')
{
// End of line or data
if (line_index > 0)
{
line_buffer[line_index] = '\0'; 
snprintf(log_buffer, sizeof(log_buffer), "Line: %s\r\n", line_buffer);
UART2Write(log_buffer, strlen(log_buffer));
line_index = 0; 
}
}
else
{
line_buffer[line_index++] = read_buffer[i];
}
}

current_address += PAGE_SIZE;
bytes_read += PAGE_SIZE;
}
}

 Here, The mentioned MX25_CMD_PP (0x02) , MX25_CMD_WREN(0x06) write_enable with these command able to enable the address for the corresponding function on the flashchip MX25L51245G.Setting the PAGE_SIZE as 264. For the Flash read, 

void EEPROM_Read(uint32_t page, char *buffer, uint32_t length)
{
uint32_t address = page * PAGE_SIZE;
uint32_t i, rx_data, dummy;

EEPROM_CS_LOW();

// Send Fast Read command
SSIDataPut(SSI3_BASE, MX25_CMD_FAST_READ);
while (SSIBusy(SSI3_BASE));

// Send address (24-bit address, MSB first)
SSIDataPut(SSI3_BASE, (address >> 16) & 0xFF);
while (SSIBusy(SSI3_BASE));
SSIDataPut(SSI3_BASE, (address >> 8) & 0xFF);
while (SSIBusy(SSI3_BASE));
SSIDataPut(SSI3_BASE, address & 0xFF);
while (SSIBusy(SSI3_BASE));

// Send dummy byte (required for Fast Read)
SSIDataPut(SSI3_BASE, 0xFF);
while (SSIBusy(SSI3_BASE));

// Clear RX FIFO
while (SSIDataGetNonBlocking(SSI3_BASE, &dummy));

// Read data
for (i = 0; i < length; i++)
{
SSIDataPut(SSI3_BASE, 0xFF); // Dummy byte to clock out data
while (SSIBusy(SSI3_BASE));
SSIDataGet(SSI3_BASE, &rx_data);
buffer[i] = (char)(rx_data & 0xFF);
}

// Null terminate the buffer
buffer[length] = '\0';

EEPROM_CS_HIGH();
}

Hi,

Yasashwini Nagarajan said:

but I am unable to read the continuously written data correctly.

  Sorry, I really don't know why you are reading unexpected data. You said you cannot read the continuously written data. I have a few questions. 

  - What if you just do one simple write and followed by read instead of continuously writes? Can you get it to work? This is to isolate if the problem has anything to do with writing continuously vs writing just once or infrequently. 

  - Your log string seems to be very long. Can you do an experiment to write a simple and short data? Can you read back the short data? This is to isolate if the problem has anything to do with the length of the string. 

  - I will suggest you also use a logic analyzer to look at the SPI bus and see what the data is written and read? This will help greatly in debugging your issue. 

1) I don't see any concession to page (256-byte) boundaries. It seems probable that your write to 0xEB wrapped back and overwrote 0x00. [Ref datasheet "(11) Page Program (PP)" description]. Try (as Charles suggests) writing and reading back one at a time.

2) SysCtlDelay(1000); Are you fairly certain this is longer than Tpp=5ms (max)? It looks rather short.

Yes, Before reading the continous data, I Tried to write only one data and read that one data. For that case I am able to read the data, But issue been there, when it comes to writting 3 to 5 data and then reading that whole data. To my case, firstly I need to store some set of data and then I want to read those. So, I try to such way.  

Hi,
    Will go through mentioned page once. Yes, it was too short in SysCtlDelay . I set that as SysCtlDelay(10000000). Here, I'm able to get one written data. After reading one data facing issue on reading as mentioned.