usb to serial

[adub]

I bought the usb to serial cable to use on my new laptop and have had no problems programming the picaxe.

but....

I just bought a arduino board. I thought the cable would work to program the arduino. Have had no luck doing so.

Any one else tried the usb/serial cable on any other boards?

Very frustrating.
Arvin

 

[manuka]

I've used many USB-serial cables (some with %&*#%^ mixed results...), but have found the classic Rev.Ed one bullet proof. Is yours this or their very new slimline one?

This is of course a Picaxe forum, so woes with other platforms are really OT. Stan

Edited by - manuka on 20/06/2007 01:49:54

 

[hippy]

I've not used USB-to-Serial, but cannot see any reason that it wouldn't work if it does with a PICAXE. You don't say which USB-to-Serial cable you are using, but things to check for are - wrong line level voltages, inverted line levels, wrongly wired pins, crossed-over/swapped lines, incorrect handshaking configuration.

I don't know the Arduino so have no idea what requirements that or the program downloader has.

 

[demonicpicaxeguy]

i've also been using it the rev-ed supplied one and it's pretty much invincible just check you've got the correct port number,that the picaxe download curcuit is ok
and that it's got a regulated powersupply

 

[xstamp]

Regarding demonicpicaxeguy comments about the need to use a regulated supply when programming a PICAXE, I recently experienced the following problem.

I was using a MAX619 regulated charge pump to provide a 5V supply to an 18X, from a small 3.6V NiCad battery. As the MAX619 is guaranteed to supply an output of 50mA from an input thats down to 3V, everything worked fine at the circuitry average draw of a few mA.

However, all attempts to programme the PICAXE in-circuit failed a few seconds into each try. After spending too much time (checking my wiring and swapping 18X chips and serial cables etc) the problem was overcome by increasing the output capacitor of the MAX619 from 10uF to 22uF.

Although a DVM showed that the circuit draw only increased by about 5mA during programming, this is only an average and I suspect that the charge pump regulator was having trouble responding to surges in demand. For low power circuitry the lesson would seem to be, even when a regulated power supply is normally reliable it may not be up to the demands of in-circuit programming.

 

[demonicpicaxeguy]

normally as a rule with any application where reliability is needed,
i tend to stick to a regulated 5v supply capable of a few amps based around a simple 7805 regulator and a capacitor curcuit
i have taken the 7805 right up to 14.4volts without damage which makes it a fairly versitile regulator
interestingly enough it's a very good regulator to use if you are doing a picaxe project in a car where there is a high amount of "noise" and transient voltages

the best approach i believe to everything is to use the simplest solution to a problem you can,
the picaxe will run at voltages down to 3v and maybe lower it will also allow a download at 3v

if you have access to an oscilliscope have a quick look and see how clean and regulated the power to the picaxe actaully is

try running the picaxe directly off the 3.6v battery it should still work perfectly
however adc usage might be a little iffy

what is the intended use for the picaxe?



Edited by - demonicpicaxeguy on 20/06/2007 10:46:58

 

[hippy]

I think we may be straying away from Arvin's actual problem; it's not programming a PICAXE that's a problem, but programming an Arduino. That's generally off topic for here but it is a question relating to a Rev-Ed product and I'm sure Arvin will tell us the Arduino and PICAXE will be married-up once it's all working.

 

[demonicpicaxeguy]

just out of curiosity what is the audrino going to be used for and why can't the picaxe do what you need?

 

[bcj]

Re regulated supplies,

Check out the LM2940
These are avaialble in a few set voltages (5, 8, 9, 10, 12 & 15) but are designed for use in Cars - i.e. have all the protection required and are very stable in the varying supply voltages prevalent in car electrical systems.

Sure they cost a bit more but only require the two caps, no reverse connection diodes or other stuff as these chips are well protected for transients, reverse connection etc etc. They operate at up to 26V in and can tolerate up to 45V before risk of failure.

Edited by - b c Jones on 20/06/2007 12:31:51