ISO High-Speed Interface with Motorola MC33290

Munysoft · 04-06-2005, 02:16 PM

First of all hello to everyone in the forum.

I've found this schematic for a "High-Speed ISO Interface" with a Motorola Chip, the MC33290, this chip it's a ISO K Line Interpreter. I'm trying to build this interface but it dosn't work... I have a few doubts, The pinout of the chip in the schematic is not the same of the Motorola Datasheet. I've tried with many ways to connect the MAX232 but I can't make it work

Anyone could make it work??? please contact me. I have a lot of info to trade

P.D: Sorry about my lacky english

shotgunefx · 04-06-2005, 02:43 PM

Do you have a link to the schematic your trying to build? Not a lot to go on here. What type of max232 do you have? Do you have the 5 external 1uF capacitors? I'm not electronics wiz by any stretch, but I've used the max232ab a few times and come across it a lot in things I've read.

Munysoft · 04-06-2005, 03:01 PM

Here's the link to the schematic http://www.skpang.co.uk/highspeed-iso9141.htm

I'm using a MAX232N from Texas Instruments with 1uF external capacitors. The MAX of the Schematic it's an MAX232ACSE (or MAX232A...it's the same) but I couldn't find it here, the only difference that I've noticed between the MAX232 and the MAX232A it's the Data Rate (kbps).. 120 for 232 and 200 for 232A, and the external capacitors.. But I have to work as well with the 232 as with the 232A no??....

I'm using VAG-COM software, in the test appears "Interface not ready"... If you know another soft that may work with this interface please let my know!!

Thanks!!!!

shotgunefx · 04-06-2005, 03:27 PM

Quote: Originally Posted by Munysoft

Here's the link to the schematic http://www.skpang.co.uk/highspeed-iso9141.htm

I'm using a MAX232N from Texas Instruments with 1uF external capacitors. The MAX of the Schematic it's an MAX232ACSE (or MAX232A...it's the same) but I couldn't find it here, the only difference that I've noticed between the MAX232 and the MAX232A it's the Data Rate (kbps).. 120 for 232 and 200 for 232A, and the external capacitors.. But I have to work as well with the 232 as with the 232A no??....

I'm using VAG-COM software, in the test appears "Interface not ready"... If you know another soft that may work with this interface please let my know!!

Thanks!!!!

Could be any number of things so not sure what to tell you, did you check the easy stuff like solder joints with a multimeter? Did you test the power regulator?

Munysoft · 04-06-2005, 03:39 PM

I'm, doing it in a protoboard, the power regulator it's OK, I've checked and all appears to be fine but it dosn't work....

Please tell me anything you think it could be, I'm runnig out of ideas :S....

Thanks

shotgunefx · 04-06-2005, 03:51 PM

Quote: Originally Posted by Munysoft

I'm, doing it in a protoboard, the power regulator it's OK, I've checked and all appears to be fine but it dosn't work....

Please tell me anything you think it could be, I'm runnig out of ideas :S....

Thanks

Like I said, I'm no expert by any means. It could be a bad chip, I've had it happen. Normally breadboards are ok as long as the circuit speed isn't too high, and you're talking upwards of 4MHZ, so that shouldn't be a problem. You said the pinout was wrong, which one? The motorola chip? Did you wire it according to the schematic or the datasheet? You might want to try adding leds and appropriate resistor to RX/TX so you can see if anything is being transmitted or received.

Munysoft · 04-07-2005, 12:46 PM

In the datasheet appears one pinout and in a drawing next to this pinout appears another!!!

I found the correct datasheet, used the pinout from there (It's the same as the schematic) and still doesn't work, I changed the MAX232 and the MC33290 4 times to be sure.... NOTHING HAPPENED!!!

Thanks!!!!