system runs at clock rate of 1.77MHz, and some of You would say one can run with a murder with such slow clock rate
so i've did what datasheet says - added inverter to phi2in signal, and used this as my LE signal driving AHCT574 - system won't even boot up
okay, time for debug with logic analyser
LA says, that there is less than 10ns (even at 1.77MHz) to latch address bits, but also shows that propagation delay for my inverter gate was too large to enable
simple way out to use '123 chip and shorten LE signal, so it could be back in time with address bus/data bus multiplexer
and so i did
system boots up, but shows that RAM chip is bad
if i pull latch out of the board, and use jumper wire tieing A16 (i'm using 628128 SRAM chip) to any constant potential, then it behaves like it should
i'm pretty clueless at the moment, as it seems that bus addresses are latched properly (i'm having constant 0 on A16 when latch is latched) - maybe my data buffer is too small to see anything wrong with the circuit
Anyways, any help would be greatly apreciated
Candle
