flashtest.c

This a simple bootloader for AT91SAM7{S,X}{64,128,256} processors. It permits you to download new c

// Flash memory store/recall for the Olimex SAM7-P256
//
// Public domain software by Adam Pierce  http://www.doctort.org/adam/
// You may freely copy this and use it for whatever purpose you like.
// 15-Apr-2007
//
// This is example code which accompanies the article at http://www.doctort.org/adam/nerd-notes/arm-flash-memory.html
//
// Operate this by using a serial terminal connected to the first serial port on the ARM dev board.
//

#include "AT91SAM7S256.h" // Definitions of the ARM chip and on-chip peripherals.
#include "Board.h"        // Definitions of peripherals on the Olimex dev board.
#include <stdio.h>
#include <string.h>

// Macro to activate a peripheral on the ARM7.
#define ARM_ACTIVATE_PERIPHERAL(id) AT91C_BASE_PMC->PMC_PCER = 1 << (id)

// Switches the given PIO pins from PIO function to a different peripheral.
#define ARM_ROUTE_PERIPHERAL_A(pPio,mask) { pPio->PIO_PDR = mask; pPio->PIO_ASR = mask; }

// We will store our data in the last page of Flash.
#define OUR_FLASH_ADDR (AT91C_IFLASH + AT91C_IFLASH_SIZE - AT91C_IFLASH_PAGE_SIZE)

#define COMM_SPEED 9600

#define AT91C_MC_WRITE_KEY  ((unsigned)0x5A << 24) // Value to enable flash commands.

// ***************************************************************
// ** flashInit - Sets up the flash writing peripheral. Call this
// **             before you do any flash writes.
// **
void flashInit()
{
// Get base location of memory controller peripheral.
	volatile AT91PS_MC mc = AT91C_BASE_MC;

// Enable the auto-erase feature and set up flash write timing.
	mc->MC_FMR = AT91C_MC_FWS_1FWS | (1 + (((MCK * 15) / 10000000)) << 16);
}


// ***************************************************************
// ** flashWrite - Write the given data to the given address in
// **              Flash memory. Erases the 256 byte page before
// **              writing.
// **              address must be DWORD-aligned.
// **              data must not cross a 256-byte boundary.
// **              Returns nonzero on successful write.
// **
int flashWrite(unsigned address, const void *data, unsigned size)
{
	unsigned i;
	unsigned page;
	unsigned *src  = (unsigned *)data;
	unsigned *dest = (unsigned *)address;

// Get base location of memory controller peripheral.
	volatile AT91PS_MC mc = AT91C_BASE_MC;

// Calculate the number of DWORDs to be written.
	size = (size + 3) / 4;

// Copy the data into the flash write buffer (this must be done 32 bits at a time).
	for(i = 0; i < size; i++)
		dest[i] = src[i];

// Write the page to Flash memory.
	page = ((char *)dest - AT91C_IFLASH) / AT91C_IFLASH_PAGE_SIZE;
	mc->MC_FCR = AT91C_MC_WRITE_KEY | AT91C_MC_FCMD_START_PROG | (page << 8);

// Check for errors.
	if(0 != (mc->MC_FSR & AT91C_MC_PROGE))
		return 0;

// Wait for write cycle to complete.
	while(0 == (mc->MC_FSR & AT91C_MC_FRDY))
		;

	return 1;
}


int main()
{
	volatile AT91PS_PIO    pPioA  = AT91C_BASE_PIOA; // PIOA
	volatile AT91PS_USART  pPortA = AT91C_BASE_US0;  // Serial port A

	char buf[96];
	int  size;

// Set up PIOA device.
	ARM_ACTIVATE_PERIPHERAL(AT91C_ID_PIOA);

// Set up US0 serial port.
	ARM_ACTIVATE_PERIPHERAL(AT91C_ID_US0);  // Enable serial port 0.
	ARM_ROUTE_PERIPHERAL_A(pPioA,US0_MASK); // Route to external pins.

	pPortA->US_CR = AT91C_US_RSTRX  // Reset Receiver.
	              | AT91C_US_RSTTX  // Reset Transmitter.
	              | AT91C_US_RXDIS  // Receiver Disable.
	              | AT91C_US_TXDIS; // Transmitter Disable.

	pPortA->US_MR = AT91C_US_USMODE_NORMAL   // Normal Mode.
	              | AT91C_US_CLKS_CLOCK      // Clock = MCK.
	              | AT91C_US_CHRL_8_BITS     // 8-bit Data.
	              | AT91C_US_PAR_NONE        // No Parity.
	              | AT91C_US_NBSTOP_1_BIT;   // 1 Stop Bit.

	pPortA->US_BRGR = (MCK/16/COMM_SPEED);   // Compute baud rate divisor

	pPortA->US_CR = AT91C_US_RXEN   // Receiver Enable
	              | AT91C_US_TXEN;  // Transmitter Enable
// Initialize flash write peripheral.
	flashInit();

	printf("Flash memory test by Adam Pierce - http://www.doctort.org/adam/\n\n");

// Retrieve string from Flash memory.
	if(*OUR_FLASH_ADDR != 0xFF)
		printf("Current data: %-80s\n", OUR_FLASH_ADDR);

// Ask the user to enter some text.
	printf("Enter some text (up to 80 characters) > ");
	scanf("%[^\r]", buf);

// Write that text to the flash memory.
	size = strlen(buf) + 1;
	flashWrite(OUR_FLASH_ADDR, buf, size);
	printf("\nWrote %d bytes to flash at address 0x%08X.\n\n", (3 + size) & ~3, OUR_FLASH_ADDR);

// Exit back to SAM-BA.
	return 0;
}