In SX Microcontrollers, SX/B Compiler and SX-Key Tool, tdg8934 wrote:

Metron,

I tried your code and {my code (attached)} on the Parallax Professional Development Board and got nothing. I then used a separate solderless breadboard (not on the PDB) and only wired +5v and GND from the PDB to it as well as ran 2 wires from the PDB Y1 jack to the separate solderless breadboard for OSC1 and OSC2 signals. Remember all I have going from the PDB to the separate solderlessbreadboard (similar in your setup) is +5v, GND, OSC1 and OSC2. 

On the separate solderless breadboard, I wired up a SX-28, 8255 and 8 LEDs/resistors. The 4 lines of +5v, GND, OSC1 and OSC2 were connected from the PDB.

I only connected the 8 LEDs/resistors to PA0-PA7. Of course I connected the D0-D7 8255 lines to RC.0 - RC.7 and 5 control lines (RESET, /WR, A0, A1, /CS) to the SX-28 (RB.0 - RB.4). On the 8255 (+5v on pins 26, 5) (GND on pin 7). On the SX-28 (+5v on pin 2) (GND on pin 4). The SX-28 had a 10K resistor from +5v to pin 28 (/MCLR) as it shows in the PDB schematic. The OSC1 and OSC2 PDB lines were run into pins 27 and 26 (SX-28) respectively. The +5v and GND lines were run from the PDB to the separate solderless breadboard. 

At this point everything is setup correctly to at least look at the 8255 Port A.

SUMMARY: 

Your "SXBtest.sxb" program gave me no outputs on the LEDs when programmed on either the PDB SX-28 or the separate solderless breadboard SX-28 circuit. 

 

However, I did run my code (attached) and IT DID WORK as expected. 

 

WHAT DOES THIS MEAN?

 

It first tells me that something on the Parallax Professional Development Board is not making contact. Normally I seem to have no problems programming it on the PDB (or separate solderless breadboard) and can even send HIGH and LOWs to the on board LEDs/resistors. 

 

I will try replacing part by part back onto the PDB and try to get my code working again. Once I find out what the culprit problem is with the PDB, I may need to call Parallax up to see if anything can be done. 

 

Once this is resolved and get "something" working on a combinational effort between the PDB and the separate solderless breadboard, I will see what the differences are between Metron's SXBtest code and mine. 

 

I have never seen this much trouble in my life in troubleshooting irregularities on 2 different setups. 

 

It has certainly been a lesson learning experience in my life. 

 

Comments????

 

Thanks for putting up with my persistance to solve this strangeness.

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