Dear Nagarajan,

Good luck. The application that you have described is going to call for a good amount of coding.

Here are some tips :

- 19 Digits of display. First and foremost decide on the interface hardware - in an application for 18 digits I have used a 4to16 decoder for digits upto 16 and 17 , 18 were directly ported to P1.4 and P1.5 ( P1.0 to P1.3 were driving the 4to16 decoder ) The segment bus was driven by PO port. Also note that you need to use a latch like 74573 for each digit. This will reduce your update frequency - we were happy with 50mS updates because of the latch. Hope you get the idea.

- With the above logic you dont need to update the displays like crazy every 1mS.

- The matrix keybboard will need 16keys minimum to read 64 keys. The ADC data will need another 8 bits as inputs. I am afraid you will very fast run out of port pins with normal 8052s.

- In such cases switching over to memory mapped I/O is a good alternative.

Reply if I have managed to confuse you !!

Bye

Raghu