With most new computers coming out without a traditional COM (RS232) port, PICAXE users must find alternatives to program the chips. The most reliable method is to purchase the AXE027 USB PICAXE programming adapter cable, and use it as directed. However, some PICAXE users simply cannot afford that option. There is an alternative cable on the internet doing the exact same thing for a cheaper price, but still more than some users can really afford, or more than a particular project budget might allow. For those users, a USB-to-RS232 serial port adapter is a possible alternative. However, most of those adapters do not interfce properly with PICAXE programmers for a couple different reasons, makign it hard to find an adapter that WILL work without trying different ones and hoping you'll find out. I found one on Ebay. It is based on the Prolific PL-2303HX chipset, and costs less than 8 dollars in US currency at the time of this posting. http://www.ebay.com/itm/231321755660 will take you to the listing for details. I picked one up to try, and it is working on all of my PICAXE serial programmers without a hitch.
For PICAXE users on a budget: $8 USB to Serial Adapter Working for Picaxe
- Thread starter DTB Radio
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Jeremy Harris
Senior Member
One problem is that there are large numbers of Chinese knock-off PL2303 adapters around, and there is no way of knowing for sure if they will or won't work, or whether they will work with a Picaxe or not.
For a time, Prolific started playing games that meant that their driver wouldn't work with some of the Chinese knock-offs, so you could buy an adapter in good faith only to find that it wasn't supported by any driver. There are some ways around this, and I've not kept up to date on the current position, but do recall there being a lot of unhappy people who had bought Chinese knock-off PL2303 units and then had problems getting them to work.
For a time, Prolific started playing games that meant that their driver wouldn't work with some of the Chinese knock-offs, so you could buy an adapter in good faith only to find that it wasn't supported by any driver. There are some ways around this, and I've not kept up to date on the current position, but do recall there being a lot of unhappy people who had bought Chinese knock-off PL2303 units and then had problems getting them to work.
Hi,
There is always going to be a risk that adapters purporting to use the (expensive) Prolific or FTDI chips may prove to use "fakes". But the much cheaper (Chinese designed) CH340 chip mentioned above does support the necessary "Break Signalling" and is much less likely to be faked.
The CH340 has now become a reasonably "credible" alternative, probably even the "preferred" interface chip on "clone" Arduino boards (due to the "dirty tricks" drivers produced by FTDI, etc.). So to get a "known good" USB-RS232 (TTL) interface chip, you could get an Arduino Nano from China for about $2.50 and add the inverters as above (or previously suggested by Goeytex). Or perhaps somebody will write (or has written) an Arduino sketch to deliver inverted TTL (i.e. true RS232, suitable for a PICaxe) directly from the nano?
Cheers, Alan.
ADDENDUM: I was going to "recommend" one of the Chinese "Blue" USB-RS232 adapters but was concerned that there might be an issue with drivers for more recent versions of Windows. Many of the listings actually say that Vista (and presumably later versions) are not supported! But it does appear that drivers even for Windows 10 64-bit are available for the CH340.
Take a look at the following two ebay listings which at first glance appear almost identical (except for 7p):
http://www.ebay.co.uk/itm/USB-to-RS232-Serial-Port-9-Pin-DB9-Cable-Serial-COM-Port-Adapter-Convertor
http://www.ebay.co.uk/itm/USB-to-RS232-Serial-Port-9-Pin-DB9-Cable-Serial-COM-Port-Adapter-Convertor
However, on close inspection one claims to use a PL2303 chip (probably a fake) and the other a CH340, but I wonder if the sellers really know what they are selling? I suspect that either seller would actually send a CH340-based device, which probably can be used with Win10 drivers. So if I were on a tight budget (and patient), I'd probably give the CH340 (claimed) one a try.
There is always going to be a risk that adapters purporting to use the (expensive) Prolific or FTDI chips may prove to use "fakes". But the much cheaper (Chinese designed) CH340 chip mentioned above does support the necessary "Break Signalling" and is much less likely to be faked.
The CH340 has now become a reasonably "credible" alternative, probably even the "preferred" interface chip on "clone" Arduino boards (due to the "dirty tricks" drivers produced by FTDI, etc.). So to get a "known good" USB-RS232 (TTL) interface chip, you could get an Arduino Nano from China for about $2.50 and add the inverters as above (or previously suggested by Goeytex). Or perhaps somebody will write (or has written) an Arduino sketch to deliver inverted TTL (i.e. true RS232, suitable for a PICaxe) directly from the nano?
Cheers, Alan.
ADDENDUM: I was going to "recommend" one of the Chinese "Blue" USB-RS232 adapters but was concerned that there might be an issue with drivers for more recent versions of Windows. Many of the listings actually say that Vista (and presumably later versions) are not supported! But it does appear that drivers even for Windows 10 64-bit are available for the CH340.
Take a look at the following two ebay listings which at first glance appear almost identical (except for 7p):
http://www.ebay.co.uk/itm/USB-to-RS232-Serial-Port-9-Pin-DB9-Cable-Serial-COM-Port-Adapter-Convertor
http://www.ebay.co.uk/itm/USB-to-RS232-Serial-Port-9-Pin-DB9-Cable-Serial-COM-Port-Adapter-Convertor
However, on close inspection one claims to use a PL2303 chip (probably a fake) and the other a CH340, but I wonder if the sellers really know what they are selling? I suspect that either seller would actually send a CH340-based device, which probably can be used with Win10 drivers. So if I were on a tight budget (and patient), I'd probably give the CH340 (claimed) one a try.
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Yes, the AXE027 Cables supplied by Rev-Ed are pricey. But this is mostly because they use a high quality and genuine FTDI chip that supports the signal inversion required to program a Picaxe. Even in bulk these chips alone cost about $6.00 each. The high cost is passed on to the users. However, it is the most reliable way to program a Picaxe.
Most, if not all of the $5 "FTDI" boards found on a popular auction site are counterfeits. Many times these fakes cannot be programmed with the FTDI utility to invert the data lines as required by Picaxe. All I can say is buyer beware on these.
I originally used Si CP2102 USP/TTL adapters (sourced from the same auction site) with added external inversion circuitry. I later found out from my sources at Silicon Labs that these too were mostly counterfeit chips, though they worked well.
Same with Prolific 2303, buy from Fleabay, BackalleyExpress, BadDealXtreme, (and others) and you likely get a fake that may or may not work. This is the price we pay for being cheapskates and using shady sources.
Now when I need to program a Picaxe with the laptop I use a CH340 based Adapter that also shares duties as a programmer for some Dorji RF modules. Never a problem with the CH340 and they are inexpensive.
But mostly I use a real serial port since I have a Dell Optiplex GX280 (WIN7) in the Lab with 2 real serial ports. I just took some old serial mice, cut off the cables, and soldered on some header connectors to make the programming cables.
Most, if not all of the $5 "FTDI" boards found on a popular auction site are counterfeits. Many times these fakes cannot be programmed with the FTDI utility to invert the data lines as required by Picaxe. All I can say is buyer beware on these.
I originally used Si CP2102 USP/TTL adapters (sourced from the same auction site) with added external inversion circuitry. I later found out from my sources at Silicon Labs that these too were mostly counterfeit chips, though they worked well.
Same with Prolific 2303, buy from Fleabay, BackalleyExpress, BadDealXtreme, (and others) and you likely get a fake that may or may not work. This is the price we pay for being cheapskates and using shady sources.
Now when I need to program a Picaxe with the laptop I use a CH340 based Adapter that also shares duties as a programmer for some Dorji RF modules. Never a problem with the CH340 and they are inexpensive.
But mostly I use a real serial port since I have a Dell Optiplex GX280 (WIN7) in the Lab with 2 real serial ports. I just took some old serial mice, cut off the cables, and soldered on some header connectors to make the programming cables.
I've bought several of the $2.00 "FTDI" boards...they are counterfeit as it turns out (they were bricked by the FTDI drivers)...I un-bricked them easily enough...and every one of these has been easily programmable by the FTDI config utility, and I can invert the tX/Rx no problem. I mark a few of them as "PICAXE" and set them aside so I don't mix them up...they work great.
I use one of those cheap FTDIRL boards and it works a treat. I didn't even have to change the PID/VID values in the Linux config files. The only drawback is I couldn't invert tx/rx using the FTDI config tool. It seemed to work but when I went back to check that tx/rx were inverted they had gone back to their original settings. I got around it using a 74HCT04E inverter.
It looks like the maker has blocked any messing with the chip.
Apart from the price, another advantage is the place you save on a breadboard without the Picaxe download socket. Also, the Picaxe can be powered from the computer's USB port.
I bought mine from a chinese seller on Amazon. They're just as cheap (2.44€, post and packing free) as on ebay but with a no-hassle money-back guarantee (I've tested it).
I mostly avoid using shady sources and supporting international criminals.
I use Linux.
It looks like the maker has blocked any messing with the chip.
Apart from the price, another advantage is the place you save on a breadboard without the Picaxe download socket. Also, the Picaxe can be powered from the computer's USB port.
I bought mine from a chinese seller on Amazon. They're just as cheap (2.44€, post and packing free) as on ebay but with a no-hassle money-back guarantee (I've tested it).
I mostly avoid using shady sources and supporting international criminals.
I use Linux.
erco
Senior Member
How old is your computer, and which OS? I've tossed a few blue PL-2303HXA cables because the HXA version isn't compatible starting with Windows 8. From http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=225&pcid=41
NOTE: Windows 8/8.1/10 are NOT supported in PL-2303HXA and PL-2303X EOL chip versions
But a CP2102 or CH340 with Goeytex's inverter works a treat.
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The genuine HL340 don't need any inverter, im unsure where Erco bought the "CH 340" and never heard of that adaptor so perhaps why it needs an inverter.
A search on Ebay for HL 340 serial adaptor will list many vendors, just ensure the product on offer is actually using the HL 340 chip.
You should be able to purchase a cable with free postage for $2.00 or less in any currency.
There is no such thing as an HL340 Chip.
"HL340" generally refers to a cable manufactured by various sources that integrates a CH340/1 Chip with a MAX232 (type) RS232 Line Driver. These cables invert the data and produce RS232 levels of approx +10 /-10V rather than the 5V TTL level used by the AX027.
CH340 or CH341 generally refers to the actual USB/TTL Bridge chips manufactured by WCH in China.
A CH340 based USB/TTL adapter (not a cable) will need external circuitry such as an inverter IC or discrete transistors to invert the data lines in order to program a Picaxe.
Attached below is a diagram of a typical HL340 Cable
"HL340" generally refers to a cable manufactured by various sources that integrates a CH340/1 Chip with a MAX232 (type) RS232 Line Driver. These cables invert the data and produce RS232 levels of approx +10 /-10V rather than the 5V TTL level used by the AX027.
CH340 or CH341 generally refers to the actual USB/TTL Bridge chips manufactured by WCH in China.
A CH340 based USB/TTL adapter (not a cable) will need external circuitry such as an inverter IC or discrete transistors to invert the data lines in order to program a Picaxe.
Attached below is a diagram of a typical HL340 Cable
Attachments
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Hi,
Thanks for that clarification Goeytex, but genuine MAX232 (or similar) chips are also quite expensive. So I suspect that many of the "Two Dollar" cables/adapters use either "fakes", or simple alternatives such as a CMOS inverter chip or two transistors.
I've just checked one of the "Blue" (CH340) adapters that I've used successfully with PICaxe for years, and although it has a DB9 connector and idles-low, the actual output levels are "TTL" (or more specifically between USB supply rails). However, that's not a bad thing since Rev Ed have now discontinued the "Enhanced" serial download diagram which was designed to better handle the negative and higher voltage levels of "real" RS232.
Cheers, Alan.
Thanks for that clarification Goeytex, but genuine MAX232 (or similar) chips are also quite expensive. So I suspect that many of the "Two Dollar" cables/adapters use either "fakes", or simple alternatives such as a CMOS inverter chip or two transistors.
I've just checked one of the "Blue" (CH340) adapters that I've used successfully with PICaxe for years, and although it has a DB9 connector and idles-low, the actual output levels are "TTL" (or more specifically between USB supply rails). However, that's not a bad thing since Rev Ed have now discontinued the "Enhanced" serial download diagram which was designed to better handle the negative and higher voltage levels of "real" RS232.
Cheers, Alan.
I wonder if all "HL340" cables use TTL levels, or if some possibly use the diagram I posted (from WCH CH340 Datasheet) and provide RS232 levels? I notice on Ebay where CH340 based cables can range from <2$ to > $9. Could the price reflect the use of a real line driver chip?
Maybe some other users who have these cables can take some voltage measurements. I do not have one to test.
Maybe some other users who have these cables can take some voltage measurements. I do not have one to test.