i am doing an eprom(2732 only) programmer for the primitive 8085 kit.Interfacing is being done thru PPI 8255.Port B and aan 8 bit latch are being used to establish the address sent from 8085 kit by the software.Port c is being is used for controlling the signal....latch...oe/vpp....latch....ce..etc.Port a is used for reading data from eprom and is set to i/p mode for that.it is also used for supplying data to the eprom ,port a is set to O/p mode for that.
I rigged up the circuit......... tested signal.....latching addressing.etc .......all that is working fine .the only glitch is my eprom reads random data for same memory location....so i am not sure of the writing either as i have no clue if what i have written is rite or rong.I have'nt used any pullups for the data lines ......could that be the problem....or something else.I have often seen pullups on data lines of eproms . could some one tell me if i need them too. and also i was wondering if i have 10k pullups will it affect the logic present at a certain pin .i have a multisim file .....i could pass the file..if u would like to help.
thanx
I rigged up the circuit......... tested signal.....latching addressing.etc .......all that is working fine .the only glitch is my eprom reads random data for same memory location....so i am not sure of the writing either as i have no clue if what i have written is rite or rong.I have'nt used any pullups for the data lines ......could that be the problem....or something else.I have often seen pullups on data lines of eproms . could some one tell me if i need them too. and also i was wondering if i have 10k pullups will it affect the logic present at a certain pin .i have a multisim file .....i could pass the file..if u would like to help.
thanx