In SX Microcontrollers, SX/B Compiler and SX-Key Tool, mlablan1 wrote:

I made some excellent progress on this journey today! 

I contacted the Maxim IC support line and an excellent Applications Engineer named Steve helped me a lot.

Based on his inputs, here are the changes I made:

1) Swapped out the 330 ohm pull-up resistor on the IRQ_not pin with a 2K ohm resistor (it is an open drain pin)
2) Put a "1" in the RM bit of the configuration input to the MAX3100 to ensure that the IRQ_not pin would work properly
3) Tied the SHND_not pin to Vcc to make sure the MAX3100 didn't go into some shutdown mode

I now have success in getting the IRQ_not pin to react to the keyboard and that means that the SX/B program can reliably wait for a full 8 bit input from the MAX3100.  

At this point my last step is to mess with 4 final variables to get a good decode from the Palm IRDA keyboard:
1) Parity on/off
2) Word length - I think this has got to be 8 bits?
3) Stop Bit (one or two)
4) Baud

I have the manual for my Palm keyboard but there is no mention on the communications settings.

I guess if I had an O-scope I could just measure the inputs from the keyboard and determine all of this, but I don't have that equipment.  Steve from Maxim IC had another idea to measure the Rx pin to try to get the timing between bits and use that to determine the baud.  I will probably try that next.

Thanks again to everyone for your help - I made some great progress today based on your inputs.  Now if I can only discover the rest of the details of the Palm Keyboard output I will be all set...

Best regards,

Mike

---------- End of Message ----------


You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=188222#m192318

Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com

The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)