PLL 40Mhz Problem

[cfernandez]

Hi,

In my design I use a EEPROM 24LC512 (Microchip) and FLASH M25PE80 (ST). When I set my code in H4 40Mhz I cannot write and read to the memory, and when I set to HS 10Mhz the memory work fine.

Can any help me?, where is the problem?

FUSE H4
#fuses H4, WDT4096, PROTECT, NOLVP
#use delay( clock=40000000 )

FUSE HS
#fuses HS, WDT4096, PROTECT, NOLVP
#use delay( clock=10000000 )

Thank you very much!!

Best Regards,

[ckielstra]

Which processor are you using?

Are you sure your processor is running at 40MHz? In order for the PLL to be enabled you have to power down the chip once, see also:
http://www.ccsinfo.com/forum/viewtopic.php?t=20325
http://www.ccsinfo.com/forum/viewtopic.php?t=23829

[cfernandez]

The only problem is with the memory, with other devices (LCD, Keyboard, etc.) work fine to 40Mhz. We are use 18F8722 with the last version of CCS.

The problem is that is too fast 40mhz for the memory?

Thanks for help me.

Best Regards,

[PCM programmer]

If you are using the delay_cycles() function, the delay time will depend
on the oscillator speed.

delay_cycles(1) is only 100 ns with a 40 MHz oscillator.
With a 10 MHz oscillator, it's 400 ns.


To fix this problem, you could change it to: delay_us(1)

Then it would stay at 1 us, if the oscillator is 10 MHz or 40 MHz.

[cfernandez]

PCM,

In my EEPROM routines not use delay, we wait for the ACK from the I2C.

void EEPROM_WaitACK( int iPage )
{
do
{
i2c_start( );
}while( i2c_write( iPage ) );

i2c_stop( );
}

Another Idea????????

[Miniman]

Can you please send me your code for the M25PE80 chip? I also have that chip, but I have not got it to work... I would be very thankful!

Best regards
Miniman

[cfernandez]

in the ST site are the source code for the memory. My company not permit send the code.

Best Regards,