topic Re: NE64 with a slowest external memory (NVRAM). in S12 / MagniV Microcontrollers

NE64 with a slowest external memory (NVRAM).

NeoSP — Mon, 05 Feb 2007 10:40:02 GMT

Dear friends,

I'm getting a big trouble with NE64 using a NVRAM as SRAM. How everybody knows, the NVRAM is slowest than SRAM. The NVRAM I'm using has a access time of 120ns, but I have to use a bus clock in 16MHz because I have to setup the SCI baud rate in 62500.

Could anybody help me to solve that? How could I use a NVRAM (Tac=120ns) with a bus clock in 16MHz? Is there any solution or idea for that?

Thanks in advance.

Neo.

Message Edited by NeoSP on 2007-02-0411:42 PM

Re: NE64 with a slowest external memory (NVRAM).

Alban — Mon, 05 Feb 2007 18:49:07 GMT

Hello and Welcome Neo,

With S12, you have the Clock Stretch possibility, look at the External Bus Interface (EBI) datasheet.

If the stretching to 8 cycles is not enough, I remember there is a WAIT (or EWAIT) possibility to wait on the external device like your memory.

May you please have a look and come back to the Forum if you need more assistance ?

Cheers,

Alban.

Re: NE64 with a slowest external memory (NVRAM).

NeoSP — Mon, 05 Feb 2007 20:19:19 GMT

Dear Alban,

Thanks for your help, but in my case, using the NE64, sinceresly, I didn't found EWAIT mode and the clock stretch, the number 3 is the maximum value allowed, but it's not enough.

Can I use some device, like an IC, in that I can stretch this pulse through of the hardware? Do you think that it will run?

Thanks in advance,

Best regards,

Marco.