barny said:One problem is that OE of the RAM should just use /RD - no need for gating with /PSEN.
Also don't understand why A15 is going to A14 of RAM/EPROM and A14 is driving Chip Select decoding. Why not use A15 as CE for EPROM and /A15 as CE for RAM?
Why do you think your board is not running ?salamander said:Hallo
But the problem is, it does not run
I have allready inserted the third eprom with the same program and so there is the question, did I something basicly wrong?!?
the error: wenn I power on the board(all parts inserted except the eprom)everything goes right(on both adress and databus is "action"), but when I insert the eprom the upper 8 bits of the adressbus are only rubish(some low, some high but no data).
usbman said:Such a scheme is needed when when you want to load user code via rom monitor. (von Neuman Architecture)
UsbMan
barny said:Fair enough. But why split A14/15? just makes it hard to load the full EPROM and there's no advantage (unless you've got old code that was written for that memory map).
It's either wiring or crystal speed. The EPROM has to be very fast to run at anything like max speed of the C320, and you need high-speed AC latch to even try, not HCT. A friend had this prob, board just didn't work until changed to 70ns EPROM and AC-type latch.
So what *is* in your EPROM?salamander said:But one thing is shure, its not a speed problem: I allready used an standard Intel 80C32 at 11.059Mhz and atleast this should run without problems, but It doesnt...
salamander
salamander said:Yes, the eprom ist ok... I have two boards here: one is the 80C515 from elektror running very well with my eprom and the other is the NEW board I posted the schematics from (with Intel 80C32 or Dallas80C320)) and when I insert the eprom in this board it behaves very very strange...
thx
salamander
if you are using a c515 monitor eprom which uses the dedicated baudrate generator for ser comunication this will only work with c515 not with 80c32 or 80c320. If you are using a 12MHz xtal with 9600 baud you will always need the baudrate generator.salamander said:Yes, the eprom ist ok... I have two boards here: one is the 80C515 from elektror running very well with my eprom and the other is the NEW board I posted the schematics from (with Intel 80C32 or Dallas80C320)) and when I insert the eprom in this board it behaves very very strange...
thx
salamander
salamander said:@usbman: you are right, but I programmed the eprom especially fro the dallas80c320(can handle multiple DPTR registers), but when I insert this eprom in my 80C515 circuit I have "action" on my address bus, but when I now insert it in the Dallas 80C320 circuit "nothing" works...
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