Universal RAM card: Bus contention possible in C1,C2 modes for top 16k bank if high rom enabled?

[revaldinho]

Need to check for bus contention in C1, C2 modes if high rom enabled while writing to top 16k of RAM. Read assertion protecting internal RAM may trigger ROM read and bus contention on data bus when writing to external RAM. Not detected by existing tests which probably don't create the right condition. Try a modified version of Duke's test.

(Potential solution may be to add diode between Ramdis and romdis if necessary on 44 pin card; 84 pin card can take a firmware update to drive romdis directly).