USB to Serial converter for programming picaxe

devian_t

New Member
I have usb to serial converter which i bought from dealextreme.com way back. I tried just hooking up the RxD, TxD and ground to the chip and I cant seem to make Linaxe detect the 08M.

Here is the things I done so far:
I installed Linaxe on my eee900 default xandros and successfully programming 08Ms and 28X1 with AXE027 before. Now I need a new AXE027 unless I can make this USB to Serial working.

My eee900 can detect the converter. Here are the info when I 'lsusb' on the terminal:[
CODE]Bus 004 Device 001: ID 0000:0000
Bus 003 Device 001: ID 0000:0000
Bus 005 Device 004: ID 0eef:0001 D-WAV Scientific Co., Ltd eGalax TouchScreen
Bus 005 Device 003: ID 05e3:0608 Genesys Logic, Inc.
Bus 005 Device 005: ID 05e3:0505 Genesys Logic, Inc.
Bus 005 Device 002: ID 0951:1606 Kingston Technology
Bus 005 Device 001: ID 0000:0000
Bus 002 Device 002: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000
[/CODE]

Now,
1. Do I have to install a driver similar to the AXE027?
2. Does Linaxe detect the chip connected even if the chip is not powered or the chip should be correctly powered before it detects it?
3. Do you think I should just buy an AXE027 or alternatives(sparkfun) rather than wasting a lot of time?
 

moxhamj

New Member
I think the answer is 3).

I've got piles of generic USB to serial converters (I got a whole lot for only $2 each). They work fine for almost everything but not so well for picaxe programming. I think the issue is there is a 'break' signal used to reset the picaxe chip and it is a non standard RS232 signal so most USB to serial devices don't implement it.

Maybe someone can add more to that but that has been my understanding of the problem.
 

hippy

Technical Support
Staff member
1) Do you have a link to what you bought from dealextreme.com ? I'm guessing it's what's showing as PL2303 and drivers are already installed. Whether the drivers installed are suitable for PICAXE use I don't know.

2) Yes, the PICAXE has to be powered and connected properly for Firmware Check and download to work. Depending on what's been previously programmed into the PICAXE you may have to perform a Hard Reset as well.

3) We recommend AXE027 as this usually avoids the hassle of trying to make an unbranded USB-to-serial cable work. We also try to give as much support as we can for official Rev-Ed product which we cannot promise for third-party product.
 

manuka

Senior Member
The many USB-serial cables lurking about can be indeed a pain in the neck when trying to link with legacy serial gear. A very recent Forum posting mentioned newer (& cheaper!) CH340 types are looking more promising however. YMMV... Stan
 

gengis

New Member
General questions on the topic of off-brand USB/RS232 converters:

Are these problems just a matter of level shifting? Would something like couple channels of a CMOS hex buffer do the trick, or discrete transistors?

Failing that a Maxim MAX232? (but that may be overkill - to add an on chip negative voltage converter when the name of the game is TTL level drivers)
 

hippy

Technical Support
Staff member
Most USB-to-serial should be giving out RS232 compatible polarities and levels so shouldn't need any inversion or level conversion. That should certainly be the case for USB to 9-way D but not necessarily for other cables or modules.

The bigger issues are usually what the chipset in the cable supports, what the drivers allow, what the quality of those drivers is and how well tuned they are for particular operating systems.
 

MartinM57

Moderator
An AXE027 would be much better...with that board you need a USB A -> USB mini cable AND a male->male 3 ring 3.5mm jack plug cable....
 

BjBlaster

New Member
Hi Guys,

I've noticed some sort of bug with LinAXEpad. I can use the "terminal" window ok to see data coming from the picaxe (08m) at any time (have a DS18B20 pumping out temp readings) but It only lets me program it if I go in and change the USB device port in settings to something else and then back to TTYUSB0.

I tried to download the latest version 1.0.3, but it seems corrupted on the rev-ed server. Is there somewhere else that has it? I was hoping it might fix the problem...

cheers

Bj
 

hippy

Technical Support
Staff member
We will investigate the issue with having to change serial ports.

The download from the Rev-Ed site was okay when I grabbed it just now and opened the file. Maybe try downloading it again.
 

hippy

Technical Support
Staff member
Using LinAXEpad 1.0.3 and an AXE027 I couldn't get any problems to arise, switching between Terminal / Debug / Downloading / Editing.

Are you using an AXE027 ? If something else it coud be a case of flaky device drivers. I couldn't see anything which indicates a fix for any serial port problem with LinAXEpad so I'd suggest downloading 1.0.3 and seeing if that does fix the problem.
 

BjBlaster

New Member
One the 4th attempt of downloading the tar.gz it finally "unzipped" ok.

1.0.3 seems to work a lot better re: the serial problem, but suffers from nfs mounted lockups when saving to a network mounted drive. 1.0.2 saves fine.

It's always something :confused:
 

hippy

Technical Support
Staff member
I don't recall any of our file saving code changing between 1.0.2 and 1.0.3 but I'll have a look to see if I have any problems. What error messages are you getting ?
 

BjBlaster

New Member
If I save to an NFS share it just locks up the application and after 1min it is still hanging so I kill it, but if I save it to the local drive it's ok. What is weird is 1.0.2 saves straight away and doesn't hang. :confused:
 
Top