Kontron VM62 - Manual (Page 61)

VM62(A) / VM42(A) User’s Manual Chapter 6 Software Configuration
12) The system software normally determines the real sizes of the DRAM and SRAM installed and re-programs the CS
lines accordingly. The simplest way to achieve this is to write a pattern to the first location and then search for that
pattern at meaningful distances (e.g. 256kB, 512 kB, 1 MB, 2 MB, 4 MB, 8 MB, 16 MB). If the pattern is found at
such an address, the original pattern must be altered and then checked to see if the mirrored pattern changes in the
same way. If not, the search must be contined or, if yes, the memory size is found.
Note
The MC68040 normally operates in non-serialised mode, meaning that read accesses can occur before
write accesses, even if they are programmed in the opposite way. It is therefore recommended that
especially when changing the patterns, a ‘nop’ instruction should be inserted, as this forces all pending
cycles to be completed.
13) Set vector and IRQ level for internal IRQ requester
• vector base = 0x40
• level = 4
0x8040.L -> CICR
14) Set SDMA configuration register 0x770.W -> SDCR
15) If the card is in the first slot, enable the VMEbus monitor
If bit 4 in VCSR is set then set bit 5 in VCSR
16) Enable on-board I/O bus error timer Set bit 2 in BCSR
May 17, 1996 © 1995 PEP Modular Computers Page 6-3