8085

Hi, I noticed that 4.7k ohm pull-up resistors are used in this circuit on the read/write memory pins: Saundby's MAG 85(scroll down to yellow text), but in other circuits where the read/write / io/m signals are decoded by the 74138 for example, pull-ups are not used? Is it because in the MAG 85...

Hi, I think that this looks correct, please confirm. I am ONLY showing my connection to the 62256 32k x 8 ram CE pin that I added to the web page picture, slide 15: When A13,A14,A15 are all low, the 2764 should be selected. When A15 is high, the 62256 should be selected. Keiichicom

Hi, When I load this code into ROM and execute it on my 8085 based computer, it works fine. The LED connected to the SOD (serial output) lights and goes out: START: MVI A,C0 ; light the LED SIM MVI B,FF ; load the delay count into the B register DELAY: DCR B JNZ DELAY...

Hi, I am still relatively new to microprocessor circuits. Please tell me how I can reduce or eliminate the noise introduced into the circuit below? I have a half-decent power supply with a stable output voltage(input about 12 volts, output about 5 volts): But there is noise in the...

Hi, I am ok on connecting one 8255 i/o chip to an 8085 mpu with an 74138 3 to 8 decoder chip but I am fuzzy on how to connect multiple 8255s? Can somebody please enlighten me, thanks?