External Memory Interface (EMI) Query

GregM — Fri, 07 Aug 2009 20:18:48 GMT

Hi,

I can't seem to get the EMI up and running correctly - and there's not much documentation about it (I'm using the DSP56F805, but I don't think my query is chip-specific)

I need to be able to address, read & write to an external memory device.

In PE (CPU Bean) I've enabled the External bus, Program Memory mode is 0B, Data Memory is Internal & External, OMR Initialise yes. Data bus width 16 bits, Address bus width 16 bits, 4 wait states, Drive enabled.

I've set 1 external memory block, with a start address of 0x2000, memory size of 0xFF, and type as RAM.

I set the start address at 0x2000 because in the memory map there's a section of Data memory labelled "External" and listed as 'not used'. It will let me set the type as ROM but only when I change the start address to the area listed as External & not used in the "Code" section of the Memory Map.

I'm not 100% sure about which option I should choose?

Assuming I've set it up correctly, how would I access the memory?

Say I wanted to access the first 2 words of the memory associated with the external device, would the following be correct?

#define FIRST_WORD_OF_DEVICE *((volatile word *)0x00002000)

#define SECOND_WORD_OF_DEVICE *((volatile word *)0x00002001)

{

word Temp;

FIRST_WORD_OF_DEVICE = 0xabcd;

SECOND_WORD_OF_DEVICE = 0xef12;

Temp = FIRST_WORD_OF_DEVICE;

}

Assuming that's correct, what address would be output on the address bus when accessing address 0x2000? Does 0x2000 appear on the bus I/O address lines, or 0x0000?

Thanks,

Greg

Re: External Memory Interface (EMI) Query

trytohelp — Thu, 13 Aug 2009 20:40:44 GMT

Hi,

I suggest you to log your request to the Freescale CRM system.
Can I suggest you to have a look to your request via the web access ?
Please use Freescale on line support web page.
- Go to following URL: http://www.freescale.com/TechSupport
- Click on Submit a Service Request to create a new one or Manage Existing Service Request.
- You will come to a login page.
- You can submit your request through the web from there or view the activities of a SR.

Pascal

topic Re: External Memory Interface (EMI) Query in Classic/Legacy CodeWarrior

External Memory Interface (EMI) Query

Re: External Memory Interface (EMI) Query