Hi all,

I'm building my first 8051 project. It's based on a 8031 with an EPROM (8k) 4k RAM, 4k NVRAM, 2x8255 and Dallas RTC.

I'm using Dunfiled's Micro-C. I wrote a small program, just to check that everything is ok - and nothing works......

I made an endless loop:

x=1;
CW8255=128;
while (x=1)
{
PORTC=0xAA;
PORTX=0x55;
}

CW8255 and PORTC are pointers to the mapped addresses of one of the 8255s.

I compiled the program using the Large model, and burned the hex file using a dedicated EPROM programmer, starting from address 0.

When i turn on the circuit, i get a clock-signal on the PSEN line, but no RD or WR lines at all (I used a logic analyzer to trace it). Due to that, i don't get any CS signals.

EA is wired down.

I checked the Demux process (`373) - seems ok.

Any ideas on what i did wrong on the way ?

Many thanks, in advance!!

Amos Freund