topic Re: Write Flash in 8-bit Microcontrollers

Write Flash

gregoryclement — Wed, 07 Sep 2016 15:27:06 GMT

Hello;

I program a microcontroller mc9s08sh4 .

I used the various discussing how to read and write to the flash . I use the example given on the forum:

I manage to save one time a character, but I can not do it after.

Here is my example code :

void main(void)
{

unsigned char Byte_To_Be_Programmed = 'D';

/* Start by copying the Flash Routine to RAM */
CopyInRAM();

/* Init Flash Clock Divider */
FlashInit();

if (Flash_Program(0xFFB0, Byte_To_Be_Programmed))
{
/* Error while programming a Byte, write your error handling here */
}

Byte_To_Be_Programmed = 'B';

if (Flash_Program(0xFFB0, Byte_To_Be_Programmed))
{
/* Error while programming a Byte, write your error handling here */
}

EnableInterrupts;
for(;;)
{

__RESET_WATCHDOG();
}

The first time , the variable 'D' ( 0x44 ) is stored in memory .

As against the variable 'B' does not register properly ( 0x40 )

Whatever the second variable , it is always 0x40 .

Do you have an idea of the problem?

Thank you for your help. DSL for my English

Re: Write Flash

kef2 — Thu, 08 Sep 2016 13:09:04 GMT

It is because you need to erase flash sector before doing second write to the same byte. First write 'D' == 0x44 clears bits so that 2 bits are left unprogrammed, bits 6 and 2, resulting byte is 0x44. 2nd write 'B' = 0x42 additionally clears bit 2 and in the end only bit 6 is left unprogrammed (=1), and you see 0x40.

Re: Write Flash

gregoryclement — Mon, 12 Sep 2016 13:28:49 GMT

Super thank you for the reply , I understand now , I'll watch it this week .

I have another question for the same microcontroller . It seems that I can put a pull-up or pull-down on my entries.

When enabled, the IRQ pin, defaults to use an internal pull device (IRQPDD = 0). The device is a pullup or pulldown depending on the polarity chosen. If the user uses an external pullup or pulldown, the IRQPDD can be written to a 1 to turn off the internal device.

By cons , I can only put a pull-up . How to put a pull-down ?

Re: Write Flash

gregoryclement — Fri, 23 Sep 2016 12:15:09 GMT

Hello;  I finally have another problem to record in the flash memory. Using Processor exprert, I am able to register in the flash several times. By cons, by modifying the code to have interrupt every 15 ms,I can not save a block and 
everything seems to hang. 

Here are some of the code: 

for(;;) // main
 { 
 
 if(Seconde%5 == 0) // every 5 seconds
 {
 IFsh1_EraseSector(0xFFB0); //Erase
 Data = Seconde;
 IFsh1_SetLongFlash(0xFFB0, Data);  //Record
 }
 
 }
void TI1_OnInterrupt(void) // Event.c
{
 DifTimer++;
 
 if(DifTimer == 64)
 {
 DifTimer = 0;
 Seconde++;
 }
 
}
I have tried disabling TI1_OnInterrupt (void) and disable interrupts, but it did not work

Which solution I have to direct me to have a intetturption every 15 ms and to record? 

Thank you for your help

Re: Write Flash

kef2 — Fri, 23 Sep 2016 12:35:02 GMT

You are erasing interrupt vectors table... Look in your SH4 manual for flash sector (page) size. It is as 512 bytes. Erasing sector at 0xFFB0 you erase everything between 0xFE00 and 0xFFFF