Den Sat, 20 Apr 2019 11:24:26 +0200 skrev Michał Pleban <lists_at_michau.name>: > > > I had to go check the code to be sure, but currently, all writes go > > to the bus, regardless of state. However, it does raise the > > question of whether the real 6509 places the address or data or a > > proper r/w signal on the bus during a read or write to $0 or $1. > > > > Michal? > > Yes, it does place the address and R/W signal on the bus when writing > to $0/$1 but not data, so the underlying RAM is overwritten with what > was previously floating on the data bus. So in practice it's almost more or less useless to have 6509 code in any of the regular ram banks while running the 8088 card, unless the 8088 software somehow protects the first two addresses in that 64k block. :O -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2020-05-29 21:29:05
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