Reading from External Hex Address...

[sbouda]

Hey all,

Ive used pics on and off for a while and just recently made a TPS and AFM volt and percentage display but now im onto a new project. Im using if its adequite a 16F877A.

I am trying to make a Nissan ECU reader using a pic similar to http://www.ecutalk.com which also uses a Pic and plugs into the Consult port of the ECU.

I have a list of Hex addresses and the scaling so i know what address on the ECU is for what.

Basically what im trying to do is send a HEX string to the ECU to initialise it to output (in which case its 0xff 0xff 0xef) and then read from the TX/RX port of the ECU a certain hex address, in which the ECU will send out as a byte or bytes, which the pic will then using some math will convert it to the right value to display on an LCD.

For example: Coolant Temp from Hex address 0x08.

How would you go about this? this is where im stumped - ill keep searching the forum but ive searched for a we while and nothing yet.


Also, another - would an extra chip be required to read the TX/RX lines then the pic reading that chip? Max232 for example? or can i just connect straight to the chip?

Just a note, people have made RS232 adaptors to plug in a computer to the ECU (schematics are freely available on the net), so what im trying to do is replace the computer side with a standalone unit like the one above using a 16x4 or larger LCD.

Thanks.

Im using PicBasic Pro 2.46 as the compiler.