User manual

Appendix B Programmable Configurations

a24_byte_write(202FFF, writecount & 000000FF);

do {

a24_byte_read(202FFF, temp);

} while (temp != writecount & 000000FF);

}

else { /* write limit reached */

print("Write limit reached - can't write.");

}

a24_byte_write(20075B, 01); /* clear IOCONFIG in VMCR2 */

The following sections describe the features that you can configure by

writing to the EEPROM on the VXI-MXI-2.

VXI-MXI-2 Requested Memory Space

The VXI-MXI-2 requires at least 16 KB of either A24 or A32 space.

You might want to change the amount of space requested or whether

the VXI-MXI-2 is an A24 or A32 device. This is especially important

when changing the amount of DRAM installed on the VXI-MXI-2. The

amount of space requested by the VXI-MXI-2 should match the

amount of DRAM installed. Set it to 16 KB when no DRAM is

installed.

Caution: If you install DRAM into the VXI-MXI-2, do not attempt to use the

first 4 KB of memory space. This 4 KB space maps to the registers on

the VXI-MXI-2 and does not access onboard DRAM. Accessing this

region will cause your VXI-MXI-2 to behave incorrectly.

If you do not want to lose 4 KB of DRAM you can get around this

limitation by setting the requested memory to double the amount that is

installed on the VXI-MXI-2, because the DRAM is aliased throughout

the remainder of the requested memory space. The DRAM should then

be accessed in the upper half of the requested memory space.

To change whether the VXI-MXI-2 is an A24 or A32 device, write the

EEPROM byte at offset 2016 hex from the VXI-MXI-2 base address.

Write a 4F hex for A24 or a 5F hex for A32.