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Actually I have to receive the 3-bytes thorough serial link and then these three bytes are then converted into paralell. I use 74245 buffer and then use three 74LS373 latches....But the problem is that there is only first byte present at all the latches.Then I debug this by connecting two latches instead of three to check the 74LS373 working,The code is as below
org 0h LE1 bit P1.1 LE2 bit P1.2
mov P1,#00h ;clear Port1 main: mov P2,#0AAh ;place dats on port2 which is data port for byte. setb LE1 acall delay clr LE1
acall delay ; wait for sometime before placing the next data
mov P2,#55h setb LE2 acall delay clr LE2
sjmp main
delay: mov r2,#250 here : djnz r2,here ret end
When I dump the following code then is appear to be toggling on both latches...... I have tried many times but cant get the exact reason for this Before that I have successfully interface the 74LS373 for data/address demultiplexing in 8051
You claim this is ARM, which it obviously isn't. You forgot to tag your code, which makes it very hard to read. Maybe you solder just as carefully?
Take a multimeter and measure your latch-enable signals while single-stepping. Or write a program that activates them one at-a-time with á couple of seconds delay between. Don't worry about the P2 data until your latch-enable signals works.
So i got the thing fixed. All i needed to do was to load R2 with 237 in line 74.
mov r2,#237;set port pin to high
Hope it helps.
Oh, of course - line 74!
How could we have missed that??!