sd_flash_write

[Nasib]

PLease, could anyone provide me a code exaple on which i can learn how to use sd_flash_write & sd_flash_erease ? 

I tried to use them but keil give me this : 

.\_build\nrf51822_xxac.axf: Error: L6218E: Undefined symbol flash_word_write (referred from main.o).

Thanks 

[Jørgen Holmefjord]

Hi,

flash_word_write is a function defined in the flashwrite example in the SDK, this is not related to the use of sd_flash_write & sd_flash_erease. How are you trying to use the functions? Are you using them in a softdevice project?

Best regards,
Jørgen

[Jørgen Holmefjord]

How do you check that nothing is written to flash? Return code of 0 means that the function call was successful (NRF_SUCCESS). Note that the sd_flash_page_erase and sd_flash_write functions are not blocking, the softdevice will try to schedule the erase/write between BLE events. You should wait for the NRF_EVT_FLASH_OPERATION_SUCCESS event before the operations are completed.

[Nasib]

I am checking it with the debugger... the flash adress is FFFFFFFF after erasing.. and  is the same after writing

How can i wait for NRF_EVT_FLASH_OPERATION_SUCCESS  event ? 

[Jørgen Holmefjord]

Which SDK version are you using? If you are using SDK 12.3.0 (last one supporting nRF51), the events are typically passed to the function sys_evt_dispatch(), where you can pass it along to the appropriate handler. If you look at the ble_app_hrs example in SDK 12.3.0, the sys_evt is passed on to fstorage (fs_sys_event_handler()), which processes the softdevice flash events.

[Nasib]

I have done this. 

in ble_stack_init i add this: 

// Register with the SoftDevice handler module for BLE events.
err_code = softdevice_sys_evt_handler_set(sys_evt_dispatch);
APP_ERROR_CHECK(err_code);

and then i add this function: 

static void sys_evt_dispatch(uint32_t sys_evt){
fs_sys_event_handler(sys_evt);
ble_advertising_on_sys_evt(sys_evt);
}



But still the same.. the memory is erased perfectly but when i try to write it doesnt write anything...

Should i do anything else? 

[Jørgen Holmefjord]

Unless you have switched to using fstorage, you should not use the fstorage handler. You need to create your own handler and use this to set a flag when the write/erase is completed:

static uint8_t flash_operation_completed = false;

void app_sys_event_handler(uint32_t sys_evt)
{
	switch (sys_evt)
	{
		case NRF_EVT_FLASH_OPERATION_SUCCESS:
			flash_operation_completed = true;
			break;

		case NRF_EVT_FLASH_OPERATION_ERROR:
			// Handle error
			break;
	}
}

Then, inside sys_evt_dispatch, you forward the events to this function:

static void sys_evt_dispatch(uint32_t sys_evt)
{
    app_sys_event_handler(sys_evt);
    ble_advertising_on_sys_evt(sys_evt);
}

And when you do sd_flash operations, you should set the clear the flag before and wait for the flag before proceeding with another operation:

flash_operation_completed = false;
sd_flash_page_erase();
while(!flash_operation_completed)
{
    sd_app_evt_wait();
}

flash_operation_completed = false;
sd_flash_write();
while(!flash_operation_completed)
{
    sd_app_evt_wait();
}

//Read back what was written to flash

[Nasib]

THANKS A LOT !

This is working. 

I am now using this: 



pg_size = NRF_FICR->CODEPAGESIZE;
pg_num = NRF_FICR->CODESIZE-2; // Use last page in flash
addr = (uint32_t *)(pg_size * pg_num);
uint32_t buffer[3]={1,2,3};

flash_operation_completed = false;
sd_flash_page_erase(pg_num);
while(!flash_operation_completed)
{
sd_app_evt_wait();
}

flash_operation_completed = false;
devuelve= sd_flash_write(addr,(uint32_t*)buffer,3);
while(!flash_operation_completed)
{
sd_app_evt_wait();
}




sprintf((char *)data_UART, "READ %d", (uint32_t)*(addr));
ble_nus_string_send(&m_nus, data_UART, 6);


sprintf((char *)data_UART, "READ+1 %d", (uint32_t)*(addr+1));
ble_nus_string_send(&m_nus, data_UART, 8);



sprintf((char *)data_UART, "READ+2 %d", (uint32_t)*(addr+2));
ble_nus_string_send(&m_nus, data_UART, 8);




And everything works great. So i have two questions

1) should i use other way to read from memory ? (other than directly acces from (uint32_t)*(addr) ? 

2) I understand that my system has: 0xFF Pages of 0x400 words, and each word of 32 bits
    so accessing to the addr =pg_size * pg_num is accessing to the last word of the memory right?, then if i want to access to the following words i should increase or decrease addr? ( now i am increasing it as you see in the code bellow, and everything works, but this goes agains my logic )  

3) With this functions, can i write word by word in the flash memory? 


Thanks a lot