Download cable problem

C

cpedw

Senior Member
I tried to program an 08M using the AXE026 download cable - the one that connects to the laptop serial port. All a bit retro but there were reasons.

I got "Hardware not found" error so I ran the Download Cable Test. It passed the continuity test but the Voltage test showed +5.8V when 5V was expected and -5.6V when 0V should have happened. Does this show that there's a fault with either the cable or the serial port?

Subsequently I checked the 08M with the AXE027 USB cable and it still was Hardware not found. Other chips were OK so I presume this 08M is kaput. Could the download cable be the cause? The chip has been around for a long time and its history is uncertain so it's quite feasible that it was damaged before.

Derek
 
A

AllyCat

Senior Member
Hi,
cpedw said:
the Voltage test showed +5.8V when 5V was expected and -5.6V when 0V should have happened. Does this show that there's a fault with either the cable or the serial port?
Click to expand...
No, that is perfectly normal for a "Classic" RS232 (COM Port) interface, which can deliver up to about +/-15 volts levels. It shouldn't have damaged the PICaxe, provided that the standard interface (10k + 22k resistors) has been used. However, if an Analogue-Digital Converter input is being used on more recent PICaxes, then the "Enhanced Serial Download Circuit" shown on page 45 of the older (paper) Manual 1 should be used..

Therefore, it's probable that the 08M chip was already damaged, IF it doesn't respond to repeated trials of the Hard Reset procedure when using a "known good" power supply (battery).

Cheers, Alan.
 
F

Flenser

Senior Member
cpedw,

If you are able to program other chips then you have successfully confirmed that there is nothing wrong with the download cable or the software installed on windows to drive the cable and the problem is something about what is plugged in at the other end of the cable.
- Double check the download circuit that you have wired up to the 08M
- Try the PICAXE "hard reset" procedure many times as AlleyCat has recommended.
 
You must log in or register to reply here.
Top