Dear All,
Till March '06,I used to use AT89C52 for code developements,and then used to transfer the code to AT89C2051/4051 or AT89C51/52,depending on the final application.There was no problem with various "PROF.SIRICHOTE","MD.ASIM KHAN","cheap local commercial" or "costlier local commercial" programmers, either for developement or final programming with full locks.
From about AprilI,I started using AT89S52,and was very happy with its ISP facility because the speed of work improved condiderably.
AT89S52 WAS SLIGHTLY CHEAPER THAN AT89C52,I WONDERED WHY BUT FORGOT IT.
As such I am novice,and I used to use the AT89S52 as AT89C51 or AT89C2051 because I knew little about X52 features and my applications hardly demanded those.
But with AT89S52,thanks to its ISP,I started venturing into some Timer2 features and I thought I had little success.Sometimes I had to relook at what all I had done in AT89C52 days.I simply transferred my C51/52 codes to S52 and apparently found no problem.....TILL ......I jumped back to my "led dot matrix moving message display" routine.
To my horror I notice that this ram intensive routine is running partially faulty with AT89S52 but there is absolutely no problem with AT89C52.By faulty I mean fonts are corrupt for example the horizontal bar of "A" is missing and like that.
My question is why so? Is it for the cheapness that the S52 rams are not like C52 rams?Faulty code?
Remember AT89C52 has no problem with the same code/codes and board/boards.
I shall appreciate all suggestions.
With best regards
A.S.Rudra