OCD

Hi

Can some one try to explain how OCD on AT89C51RE2 works?

I dont realy understand if system debugs needs any adicional hardware when using the OCD pin?

Wht tipe of target debugs are there?
I know ISD51 from keil doesnt need adicional hardware are there any more?

BTW the main reason i want to know is to build my own dev board thats capable of in sytsten debug

Thanks in advance

Well RE2 needs a special hardware AT89OCD/ATOCD51. well i think its not difficult to make this hardware yourself. but vendors always keep themselves on a safe side

Here is more information about AT89OCD/AT)CD51:
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4049

good thing about this debugger is it uses uart so i believe there is not much they have done on hardware side except those control lines.

This document will provide little more insight on this:

is AT89C51RE2 the best option for a learning board?
If not can u gimie some examples that are compatible with ISD51

Do you have ISD51 with you? if yes then i think you can move ahead with any microcontroller available to you. Whereas if you are looking at learning prospective, then i guess you dont need a debugger. 8051 is a small controller that doesnt require a special debugger. If you really want to simulate something like uart or I/O port then you can use keil's software debugger.

For choice of 8051, i would suggest you go with any controller with ISP (in system programming) support. coz you will not be bound with any special programmer hardware. For instance Atmel's AT89C51RD2, ED2, RE2 etc
Philips P89V51RD2
Another benefit of using these ICs are they have onchip XRAM which will help you when writing bigger programs.

Do let me know what you choose