Hello all,
I am interfacing a 16x2 LCD to the AT89S8252 via memory mapping. 74LS138 is the decoder, 74LS373 is latch. RS of the LCD is connected to A0. R/W is connected to output of a latch formed with RD and WR signals. EN is connected thru an inverter to the decoder (138) output Y0 forming address 0000 to 1023 space.
The problem is that the LCD is not getting initialized at all. it only shows all dots ON on the first line. therafter nothing.
Is there any specific care to be taken while using the 89S8252? it has got two DPTRs and internal EEPROM too.
Are pull ups must to the Port 0 and Port 2? Please give some clues how to debug the things? i don't have a CRO (!!!).
THanks to all in advance.