piklab plus cheap serial port?

Quakeboy02 · 05-05-2014, 10:45 PM

My PCI 2-port serial card failed, so I got a new one that supposedly "works with linux". Yeah, it does, but it won't drive my JDM Programmer under Piklab. I've managed to rearrange my serial attachments to get all 3 serial devices working, but I was wondering if anyone had any Piklab/JDM success with a cheap PCI-e X1 2-port card? I'm a little uncomfortable only being able to drive the burner from the motherboard's serial port. This one is by IOCrest and has a MOSCHP MCS9922CV chip. Maybe it's time to get a better burner?

michaelk · 05-06-2014, 09:52 AM

I can not look at the specs for the MCS9922CV at the moment but suspect it could be a voltage level problem. IMHO really not a linux or Piklab problem. A programmer like the pikstart which needs an external power supply will work with any serial port.

Adding a buffer should work like 4 MAX232 chips (2 ea back to back) as one example. I looked at a couple of JDM burner circuits and they only used 3 232 lines plus ground.

Quakeboy02 · 05-06-2014, 11:19 AM

I see that there is a ZT3243LEEA on both ports. I guess that's not enough or they haven't provided for voltage feedthrough. They mention that it supports "Slow IrDA" and it does drive my single-LED lirc transmitter. I can take a look at a JDM circuit to see if maybe there are any options in Piclab that might do something.

I see a lot of USB programmers on ebay. Can you recommend any particular one known to work?

michaelk · 05-06-2014, 12:20 PM

Nope. I can only quote what is on the piklab's website. The ZT3243LEEA are low voltage devices i.e. 3.3 - 5.5 but the JDM programmer is labeled as a high voltage device. The JDM home page has "This Programmer is powered by the RS-232 and it works with RS-232 levels at only < ±8.6V" Not quite sure about the only < part.

Quakeboy02 · 05-06-2014, 12:43 PM

OK. I guess this board meets the trend of supplying voltages that don't meet the RS-232 standard. Thanks for your help.

michaelk · 05-06-2014, 01:26 PM

Not really. Actually the range per the RS-232 specification for a logic level is 3-15 (+ and -) volts. Typically PC serial ports used +/- 12 volts. Without the higher voltage you can't program high voltage PICs.