Dual mapping memory on the ST10F276

[wjohnson]

Posted on October 22, 2004 at 11:03

Dual mapping memory on the ST10F276

[wjohnson]

Posted on October 07, 2004 at 18:30

We are using an ST10F276, and need to ''dual map'' memory. Let me describe what we're doing. On the 168 and 269, we have our EOL flash data in 2 pages, and have a data page pointer allocated to each page (small memory model, near EOL parameters).

To allow our customer to easily calibrate the EOL, we have a command that copies the EOL into external RAM, then switches the 2 data page pointers to point to external RAM, allowing them to change EOL ''on the fly''.

On the 276, they've decided they want 4 pages for EOL, and still want this calibration function. We're also now using the large memory model. We can't use all 4 data page pointers to point to EOL, since 1 has to stay at the internal RAM/register area.

The Motorola Power PC (563/564) has a ''dual mapping'' function that we've also used to accomplish this, we just tell it what range it is supposed to dual map, and where to find it.

Is there any way to set up the external bus interface, or something, to accomplish this task??

Thanks for the help

[wjohnson]

Posted on October 22, 2004 at 11:03

To answer my own question (in case anyone else is curious), this can be done using the XADRS register, which can be used to create memory ''holes'', which can then be accessed using external memory. The XADRS register is described in section 9.7 of the ST10F276 users manual.