Question about AXE027

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rob53

New Member
I'm about to build myself a newer computer, and it won't have a serial port like the dinosaur I'm using now, so Ill obviously need a USB to Serial adapter to program my Picaxe uCs. As I already have all the components I need to build the AXE027 in the attached schematic. What I'm a little confused about is the TX and RX connections that I've circled in red, do they connect like "TX to TX" on the Picaxe (TX to Serial Out) and RX to RX (RX to Serial In), or does it mean the TX side on the AXE027 is transmitting data to the Picaxe, in which case the AXE027 TX would connect to the Serial IN side of the Picaxe. Which way is correct? One more question....will I be need to use a logic level converter with this device?
USB SERIAL ADAPTER.JPG
 
hippy

hippy

Technical Support
Staff member
The FT232RQ datasheet I have shows leg 30 as TXD, Output, so would go to Serial In of the PICAXE, leg 2 as RXD, Input, so would go to Serial Out of the PICAXE. The circuit diagram is complete and does not require any logic level converter.

We would recommend purchasing an actual AXE027 rather than building and programming your own.
 
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inglewoodpete

Senior Member
rob53 said:
I'm about to build myself a newer computer, and it won't have a serial port like the dinosaur I'm using now...
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Keep an open mind and look out for motherboards that DO HAVE a serial port header (sometimes called a Com port header). About 18 months ago I went through the exercise that you are entering and was pleasantly surprised. See if you can find a website that allow parametric searches for motherboards and you might get lucky, depending on your overall criteria. I had to order a serial-header-to-DE9 socket off eBay for about $5 but now I continue to use a standard serial cable (as well as an AXE027).

My board has the Intel B85 Express chipset, which seems to include serial port support on many motherboards.
 
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rob53

New Member
hippy said:
The FT232RQ datasheet I have shows leg 30 as TXD, Output
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that's also what it shows on the schematic, except it doesn't say "output" :)

We would recommend purchasing an actual AXE027 rather than building and programming your own.
Click to expand...
You mean I have to program it? Bummer, dude. That right there just bursted my bubble.
 
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rob53

New Member
inglewoodpete said:
Keep an open mind and look out for motherboards that DO HAVE a serial port header (sometimes called a Com port header). About 18 months ago I went through the exercise that you are entering and was pleasantly surprised. See if you can find a website that allow parametric searches for motherboards and you might get lucky, depending on your overall criteria. I had to order a serial-header-to-DE9 socket off eBay for about $5 but now I continue to use a standard serial cable (as well as an AXE027).

My board has the Intel B85 Express chipset, which seems to include serial port support on many motherboards.
Click to expand...


Yeah, I haven't gotten into selecting a motherboard yet. I could always go with BESQUEUT'S idea and just buy a PCI or a 1x or 4x PCI-E serial card
 
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Jeremy Harris

Senior Member
I've just built a cheap, small, zero noise (fanless) PC, and the MB I used had both LPT and RS232 ports, so there are certainly MBs around with RS232 ports. Programming a Picaxe via an RS232 cable seems quicker than using the AXE027 on the machines I have that don't have a serial port, too, which is another good reason to try and find a MB with RS232.

I found that MBs intended for use in industrial PCs tend to have real serial and parallel ports, as they are still used a lot in industrial control. My MB was cheap, an Ebay purchase, but is plenty fast enough for my needs, and has the advantage in the workshop in that I can programme Picaxe chips via the serial port and drive my desktop CNC router via the LPT port.
 
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nick12ab

Senior Member
inglewoodpete said:
Keep an open mind and look out for motherboards that DO HAVE a serial port header (sometimes called a Com port header).
Click to expand...
Got to agree with this option. As good as the AXE027 is, proper on-board serial ports just work without issues with drivers (because none are required) or the COM port numbers changing themselves. Most new motherboards still have serial headers (including Skylake), and some even have parallel too. I think it's more difficult to find one without serial.
 

Attachments

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oracacle

Senior Member
serial to stereo cables are easy to make yourself too.
stereo tip goes to pin 5 - 0v
stereo ring goes to pin 3 - picaxe serin
stereo sleeve goes to pin 2 - picaxe serout
 
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rob53

New Member
nick12ab said:
Got to agree with this option. As good as the AXE027 is, proper on-board serial ports just work without issues with drivers (because none are required) or the COM port numbers changing themselves. Most new motherboards still have serial headers (including Skylake), and some even have parallel too. I think it's more difficult to find one without serial.
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It seems you're right. The serial port header is listed in the motherboard specifications-->internal i/o connectors, but it's nowhere to be found in Newegg.com's "power search" parameters. Anyhow, did your motherboard include a serial cable with a bracketed 9 pin serial port?
 
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inglewoodpete

Senior Member
In my experience, most motherboards with the serial header come without the cable and bracket. Propeller-Heads like us have to order them separately, since we're the major customers but are just a small percentage of the market. If you're committed to buying a compatible motherboard, then order the cable on-line in advance for just a couple of dollars.
 
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nick12ab

Senior Member
rob53 said:
It seems you're right. The serial port header is listed in the motherboard specifications-->internal i/o connectors, but it's nowhere to be found in Newegg.com's "power search" parameters. Anyhow, did your motherboard include a serial cable with a bracketed 9 pin serial port?
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The cable and bracket weren't included, though I think that's a good thing because 99% of them would just get thrown away. The number of people needing them is very small, even PC Part Picker doesn't let you filter by serial and parallel connectors, but they're common enough that you could just look at the pictures one-by-one once you've specified the other parameters you need and you'll soon find one such equipped.
 
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rob53

New Member
nick12ab said:
The cable and bracket weren't included, though I think that's a good thing because 99% of them would just get thrown away. The number of people needing them is very small, even PC Part Picker doesn't let you filter by serial and parallel connectors, but they're common enough that you could just look at the pictures one-by-one once you've specified the other parameters you need and you'll soon find one such equipped.
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That's a good point about the cable getting thrown away. I never thought about that. Anyway, this discussion got me to looking at motherboards and I've picked one. This board is loaded with features for the price. I'm gonna scoop it up while it's still on sale
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128863

I've had some good experience with Gigabyte boards. One of the things that sold me on this board is that it has 2x M.2 slots and 2X SATA Exress slots, as I intend to go with SSD exclusively, and M.2 is supposed to be a better interface than SATA III. I've read articles that talk about how SATA III is a bottleneck for SSDs. The board is also socket LGA1151, supports SLI and Crossfire (a feature I'll probably never use). Though I don't do very much PC gaming, the games I DO play tend to be big time system hogs, but one good GPU is enough to handle them, but that will have to come later. For now I can get by with the onboard GPU on the processor (core i5 6500) and just play PS3 games until I can afford a good graphics card.

But anyway... back to the topic at hand. As Pete pointed out, I can get a serial cable w/bracketed DB9 port for just a few bucks. I'm so glad I don't have to bother with a USB programming cable for my Picaxe uCs, as the serial interface is SO simple to use, no cussing, no headaches :)
 
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