I blew the dust off my copy of Jan Axelson's USB Complete to see if there's any way the Prop could handle USB comms directly without needing the FTDI chip. Ugh! Now I remember why the book has collected dust these several years. Not that the book is bad. On the contrary: it's actually quite thorough. But the USB protocol itself is a tangled mess that one would have to be half-crazed to attempt implementing in bit-banged firmware. I'm not saying it's impossible, but there are more productive ways to spend one's time.
I didn't know that had already been done. I took a look at BradC's code, which only confirmed my estimation of the amount of work such a project entails. Wow.
On the PICAXE interface, before too much confusion sets in - That's a 9-way to stereo 3.5mm jack, 9-way to PC, 3.5mm via a simple resistor interface to the chip (PICmicro). Not true RS232 but doesn't need any MAX232 so absolutely minimal cost and cheap cable ( there's also a 9-way to 3-pin keyed molex I prefer, and easy to make one's own equivalent ). It's a pre-programmed interpreter so download is done by firmware polling a 'break' on the serial line or 'break' present when hardware physically reset.
I know the arguments against this simplistic 'RS232' interface but have had no problems with it myself and I've done the same in my own PICmicro and Propeller projects. I actually have an interface board which takes the three-wire serial (TX/RX/0V) with a 74HCxx to invert the signals and generate Reset for the Propeller from the 'break' and have used that for downloading. It does need a downloader to generate 'break' so PropTool / Propellent doesn't work, but they don't work under Win 98 anyway.
Nice side-effect is no unwanted resets when plugged or unplugged or when the port is opened, closed or probed. Also works with USB-to-Serial / FTDI.
I think you guys are missing the point. Newcomers now expect USB. It must be on the PCB, not an add-on as that adds more cost.
If I were redoing the Propeller Proto Board with USB, I would change the footprint to use cheap VGA and PS2 connectors (standard). I butchered and old motherboard to get a VGA connector onto the PPB but it is not pretty. I couldn't find the connector easily (in Australia).
I definately would not bundle USB cables or Power Packs. They are readily available everywhere (if the user doesn't already have them) and it adds to postage. As mentioned above, batteries can be used too.
Now, for us. What everyone seems to be asking for is a cheap, cutdown version of the Propeller Proto Board (without USB), no provision for VGA or PS2 connectors, no prototype area, and just pin holes for off-board connections. Unfortunately, volume is the problem. Even if the Prop chip didn't cost anything, assembly cost in Australia would be too expensive to sell for $20 - might even cost more than this. Are any of you willing to solder the surface mount propeller chip if a PCB was available???
I really like the "break" approach. Anything to eliminate an extra pin. I use it myself on a Propeller board I've designed to be programmed from a 3-pin (Vdd, Vss, open-drain I/O) interface. In my case, though, a resident monitor/bootloader looks for the break and resets the chip, rather than having it done in hardware. What circuitry did you use to stimulate a /RST from the break, BTW?
It might be worth noting that three of the four cheap dev kits I noted above are USB "stick" devices that plug directly into a USB type A socket. In the casual buyer's mind, at least, this obviates the need for a cable. In reality, of course, this is an inconvenient way to work with the board, and an extension cable quickly becomes a sought-after accessory.
I don't think the protoboard is for beginners. It's for low qty prototypes. The Demoboard is for beginners. I picture most customers buying 5 or 10 protoboards, programming them once, and being done with it. Shucks, I'd be happier if the protoboard had an eeprom socket & no connectors.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Concentrate on understanding the problem, not applying the tool
If anything needs to be 're-designed' it should be the Demo Board. If the USB programmer was pulled off of this board and the PropPlug was included with the starter kit, then when the beginner that's advancing to building more one off prototypes, would already have the PropPlug for programming Proto Boards or whatever Propeller device Parallax should make.
Maybe Parallax needs to 'run the numbers' on a potentially lower cost Proto Board type of product, to see what they can provide and at what price point. As from my posts I'm perfectly happy with a 'core module' platform. Propeller chip, crystal, eeprom (could be as small as 32K) and the necessary discrete (filter caps & pull-up resistors). Let the end user decide what else they want to add, on their own board, that this module is part of. If people are needing VGA connectors or what not then Parallax could offer adapter boards like what they have done for the RCA jack, Keyboard/Mouse connectors.
[noparse][[/noparse]quote=Cluso99]I think you guys are missing the point. Newcomers now expect USB. It must be on the PCB, not an add-on as that adds more cost.
Do they? I, when looking at a platform don't; and it's requirement can be annoying on dev boards and such since my USB ports are round the back of the PC (Reaching there is a pain), on the front (Also awkward since it's under the keyboard tray), or on the side of my monitor (Which is against a wall).
It's perfectly fine for fixed devices (like the aforementioned PICKit2).
I looked up the aforementioned PICAXE serial connection, and it sounds suitable for connection to a Prop, if the resistor is large enough. If were feeling paranoid, theres always the option of adding a zener - all cheap components. 3.3v is probably just high enough to be OK with rs232.
In my opinion flat PropBoard is not to fine to al experiments.
One of my proposo/suggestion to Paralxax is to have that model of ProtoBoard (see Picture). It is not my construction (It is Ken Peterson that construct it)but I see that construction very useful in Nobby adn even industriel aplications.
With that board You can mount it on BredBoard as wel. And it is very handy to mount it on Yours own constructions in one else X.Props board.
Regards
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Nothing is impossible, there are only different degrees of difficulty. For every stupid question there is at least one intelligent answer. Don't guess - ask instead. If you don't ask you won't know. If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
@ Clusso99 : Newcomers now expect USB - It's also my experience that more, not just newcomers, are demanding "USB" on-board. This is particularly true for first time users who want an all-in-one, works out the box experience.
@ Phil : What circuitry did you use to stimulate a /RST from the break, BTW?
@ Nick : "I don't think the protoboard is for beginners" - I think that depends on definition of beginner. I believe those who can solder and want to build things but are new to the Propeller ( isn't that how many - maybe most - of us were ? ) would start with ProtoBoard rather than DemoBoard.
Cluso99 and others said...
What everyone seems to be asking for is a cheap, cutdown version of the Propeller Proto Board (without USB), no provision for VGA or PS2 connectors, no prototype area, and just pin holes for off-board connections.
What is the advantage of such a board over a DIP 40 Propeller with externally connected crystal and EEPROM?
DIP40 Prop + EEPROM + crystal cost: ~ 15$
If you have such a minimal board, you anyway have to connect Power supply with regulator, and periphery. The additional connection of a EEPROM and crystal is so easy, that I don't see the advantage.
What is the advantage of such a board over a DIP 40 Propeller with externally connected crystal and EEPROM?
Not having to connect components up, ready-to-go, effort saved, unlikely to be wired wrong and no need to debug, plus it's much easier and cheaper to source everything in one hit from one supplier without multiple shipping costs.
You could ask why Parallax ever produced the PropStick or PDIP Basic Stamps on carriers rather than as a bag of components.
@Ken: We are going around in circles here. Would you mind telling us the % sales of the PPB (ex USB), the PPB (inc USB), and the different demo boards.
My perception is that the PPB(USB) would be most popular for beginners, whereas the experienced users mainly on this forum are buying the PPB(ex USB) for inclusion in other projects.
OwenS said "... my USB ports are round the back of the PC (Reaching there is a pain), on the front (Also awkward since it's under the keyboard tray), or on the side of my monitor (Which is against a wall)" - Really, then how do you connect the RS232??? thin air??? I don't have RS232 on any computers I currently use, and neither do my 3 kids (adults).
I think you definitely need to support USB these days - whether it's built-in or an add-on (like a prop plug). Serial ports are becoming very rare. Fewer motherboards have even one port. And it seems that more and more people are moving to laptops and don't own a desktop/tower. I don't know when the last time I saw a new laptop with a serial port was (although there are probably some out there).
Personally, I have plenty of serial ports. I've got two desktops that each have 6 so I'm usually not at a loss. But I think that's pretty unusual.
And. my laptop certainly doesn't have one (OK, my old laptop from 1992 (or so) has one - but it's got a 486 DX/2 in it so I don't use it a whole lot anymore). It would be much easier to carry around a simple USB cable than a USB-serial adapter cable. I've also been playing with doing development on an even smaller laptop (Asus EEE 901 these days) which only has USB ports.
If you don't include a USB cable with every device sold - of which most people may only require one no matter how many devices they buy - you at least need to offer one cheap. While most of us probably know where to find USB cables for $1 or so (or have so many around we don't know what to do with all of them) many other people only know about the $18 cables they are offered at Best Buy and Walmart when they buy their new printer. I've had to stop several people from buying cables from these places and just given them spares that I had lying around. You don't want someone saying that the $20 prop board is too expensive because it's going to require another $18 for the cable.
Cluso99: I have an RS232 cable sitting on my desk. I suppose it's the same either way, just that I dont tend to have a bunch of USB cables arround (Maybe I should; just I'd need to add a hub to my desk first, since my 4 back ports are full).
The advantage of RS232 of course is that it's cheap. Thats something you don't get with USB.
In most cases it is fine with RS232 but not if <You will >Run ViewPort ( Prop based osciloskope)
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Nothing is impossible, there are only different degrees of difficulty. For every stupid question there is at least one intelligent answer. Don't guess - ask instead. If you don't ask you won't know. If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Come on people, the year is 2008. Serial ports having been pinning for the fjords for many years now, they've gone the way of the dodo; I think the
discussion on their merits vs USB is irrelevant. USB has won. Modern machines only have USB and not having support for USB is suicidal.
Mind you, that is not the same as saying that the USB support has to be built-in to the board. The way the PPB does it (off-board USB to RX/TX/5v/GND lines)
feels like a reasonable approach: USB overhead paid for only once, those out there that still want serial can create their own connector using a couple of
transistors and everybody is happy.
On a different line: I highly agree with most of the other posters regarding a cheap Propstick type of propeller board. The bulk of the space on the existing
protoboards is wasted by me. I find it very hard to construct meaningful prototypes in the prototyping area (having the propeller in the middle complicates
layout and wiring) so I just put header boards around the periphery and use those to connect my stuff to (as per the Propeller Cookbook)
One of the failings of the Propeller Demo Board (which I unwisely first purchased) is the lack of access to most pins, and most specifically pins 28/29 (the pins
already dedicated to i2c for the propeller and that already have the pull up resistors). With so few pins available on the demo board that hurt.
For absolute newbie-amateurs, the education kit is a must... but 3 days later, something like the protoboard is required... I only rarely use the prototyping area and wish that it was either a bread board or a really generic PCB area with a few bus structures and holes already connected in five hole groups...I find Radioshacks generic pcbs very useful.... not enough power rails but very useful.
The nice thing is that there is a market for 3rd Party boards, which will only grow with time.
What would I like from you hardware guys:
A QFN or QFP on some kind of break out board that makes it breadboard/RadioShack/PCB compatible for around $20. No power supply... no other connectors of any kind. We are going to need one for the PropII anyway[noparse]:)[/noparse]
Comments
-Phil
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'Still some PropSTICK Kit bare PCBs left!
I didn't know that had already been done. I took a look at BradC's code, which only confirmed my estimation of the amount of work such a project entails. Wow.
-Phil
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'Still some PropSTICK Kit bare PCBs left!
I know the arguments against this simplistic 'RS232' interface but have had no problems with it myself and I've done the same in my own PICmicro and Propeller projects. I actually have an interface board which takes the three-wire serial (TX/RX/0V) with a 74HCxx to invert the signals and generate Reset for the Propeller from the 'break' and have used that for downloading. It does need a downloader to generate 'break' so PropTool / Propellent doesn't work, but they don't work under Win 98 anyway.
Nice side-effect is no unwanted resets when plugged or unplugged or when the port is opened, closed or probed. Also works with USB-to-Serial / FTDI.
If I were redoing the Propeller Proto Board with USB, I would change the footprint to use cheap VGA and PS2 connectors (standard). I butchered and old motherboard to get a VGA connector onto the PPB but it is not pretty. I couldn't find the connector easily (in Australia).
I definately would not bundle USB cables or Power Packs. They are readily available everywhere (if the user doesn't already have them) and it adds to postage. As mentioned above, batteries can be used too.
Now, for us. What everyone seems to be asking for is a cheap, cutdown version of the Propeller Proto Board (without USB), no provision for VGA or PS2 connectors, no prototype area, and just pin holes for off-board connections. Unfortunately, volume is the problem. Even if the Prop chip didn't cost anything, assembly cost in Australia would be too expensive to sell for $20 - might even cost more than this. Are any of you willing to solder the surface mount propeller chip if a PCB was available???
I really like the "break" approach. Anything to eliminate an extra pin. I use it myself on a Propeller board I've designed to be programmed from a 3-pin (Vdd, Vss, open-drain I/O) interface. In my case, though, a resident monitor/bootloader looks for the break and resets the chip, rather than having it done in hardware. What circuitry did you use to stimulate a /RST from the break, BTW?
-Phil
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'Still some PropSTICK Kit bare PCBs left!
It might be worth noting that three of the four cheap dev kits I noted above are USB "stick" devices that plug directly into a USB type A socket. In the casual buyer's mind, at least, this obviates the need for a cable. In reality, of course, this is an inconvenient way to work with the board, and an extension cable quickly becomes a sought-after accessory.
-Phil
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'Still some PropSTICK Kit bare PCBs left!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Concentrate on understanding the problem, not applying the tool
If anything needs to be 're-designed' it should be the Demo Board. If the USB programmer was pulled off of this board and the PropPlug was included with the starter kit, then when the beginner that's advancing to building more one off prototypes, would already have the PropPlug for programming Proto Boards or whatever Propeller device Parallax should make.
Maybe Parallax needs to 'run the numbers' on a potentially lower cost Proto Board type of product, to see what they can provide and at what price point. As from my posts I'm perfectly happy with a 'core module' platform. Propeller chip, crystal, eeprom (could be as small as 32K) and the necessary discrete (filter caps & pull-up resistors). Let the end user decide what else they want to add, on their own board, that this module is part of. If people are needing VGA connectors or what not then Parallax could offer adapter boards like what they have done for the RCA jack, Keyboard/Mouse connectors.
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Mike
Post Edited (Mike Cook) : 9/23/2008 10:51:33 PM GMT
Do they? I, when looking at a platform don't; and it's requirement can be annoying on dev boards and such since my USB ports are round the back of the PC (Reaching there is a pain), on the front (Also awkward since it's under the keyboard tray), or on the side of my monitor (Which is against a wall).
It's perfectly fine for fixed devices (like the aforementioned PICKit2).
I looked up the aforementioned PICAXE serial connection, and it sounds suitable for connection to a Prop, if the resistor is large enough. If were feeling paranoid, theres always the option of adding a zener - all cheap components. 3.3v is probably just high enough to be OK with rs232.
The only problem is the inversion needed...
In my opinion flat PropBoard is not to fine to al experiments.
One of my proposo/suggestion to Paralxax is to have that model of ProtoBoard (see Picture). It is not my construction (It is Ken Peterson that construct it)but I see that construction very useful in Nobby adn even industriel aplications.
With that board You can mount it on BredBoard as wel. And it is very handy to mount it on Yours own constructions in one else X.Props board.
Regards
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
Post Edited (Sapieha) : 9/23/2008 11:05:43 PM GMT
@ Phil : What circuitry did you use to stimulate a /RST from the break, BTW?
http://forums.parallax.com/showthread.php?p=694642
@ Nick : "I don't think the protoboard is for beginners" - I think that depends on definition of beginner. I believe those who can solder and want to build things but are new to the Propeller ( isn't that how many - maybe most - of us were ? ) would start with ProtoBoard rather than DemoBoard.
-Phil
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'Still some PropSTICK Kit bare PCBs left!
What is the advantage of such a board over a DIP 40 Propeller with externally connected crystal and EEPROM?
DIP40 Prop + EEPROM + crystal cost: ~ 15$
If you have such a minimal board, you anyway have to connect Power supply with regulator, and periphery. The additional connection of a EEPROM and crystal is so easy, that I don't see the advantage.
Andy
Not having to connect components up, ready-to-go, effort saved, unlikely to be wired wrong and no need to debug, plus it's much easier and cheaper to source everything in one hit from one supplier without multiple shipping costs.
You could ask why Parallax ever produced the PropStick or PDIP Basic Stamps on carriers rather than as a bag of components.
My perception is that the PPB(USB) would be most popular for beginners, whereas the experienced users mainly on this forum are buying the PPB(ex USB) for inclusion in other projects.
OwenS said "... my USB ports are round the back of the PC (Reaching there is a pain), on the front (Also awkward since it's under the keyboard tray), or on the side of my monitor (Which is against a wall)" - Really, then how do you connect the RS232??? thin air??? I don't have RS232 on any computers I currently use, and neither do my 3 kids (adults).
Personally, I have plenty of serial ports. I've got two desktops that each have 6 so I'm usually not at a loss. But I think that's pretty unusual.
And. my laptop certainly doesn't have one (OK, my old laptop from 1992 (or so) has one - but it's got a 486 DX/2 in it so I don't use it a whole lot anymore). It would be much easier to carry around a simple USB cable than a USB-serial adapter cable. I've also been playing with doing development on an even smaller laptop (Asus EEE 901 these days) which only has USB ports.
If you don't include a USB cable with every device sold - of which most people may only require one no matter how many devices they buy - you at least need to offer one cheap. While most of us probably know where to find USB cables for $1 or so (or have so many around we don't know what to do with all of them) many other people only know about the $18 cables they are offered at Best Buy and Walmart when they buy their new printer. I've had to stop several people from buying cables from these places and just given them spares that I had lying around. You don't want someone saying that the $20 prop board is too expensive because it's going to require another $18 for the cable.
The advantage of RS232 of course is that it's cheap. Thats something you don't get with USB.
In most cases it is fine with RS232 but not if <You will >Run ViewPort ( Prop based osciloskope)
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
discussion on their merits vs USB is irrelevant. USB has won. Modern machines only have USB and not having support for USB is suicidal.
Mind you, that is not the same as saying that the USB support has to be built-in to the board. The way the PPB does it (off-board USB to RX/TX/5v/GND lines)
feels like a reasonable approach: USB overhead paid for only once, those out there that still want serial can create their own connector using a couple of
transistors and everybody is happy.
On a different line: I highly agree with most of the other posters regarding a cheap Propstick type of propeller board. The bulk of the space on the existing
protoboards is wasted by me. I find it very hard to construct meaningful prototypes in the prototyping area (having the propeller in the middle complicates
layout and wiring) so I just put header boards around the periphery and use those to connect my stuff to (as per the Propeller Cookbook)
One of the failings of the Propeller Demo Board (which I unwisely first purchased) is the lack of access to most pins, and most specifically pins 28/29 (the pins
already dedicated to i2c for the propeller and that already have the pull up resistors). With so few pins available on the demo board that hurt.
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---
Jo
The nice thing is that there is a market for 3rd Party boards, which will only grow with time.
What would I like from you hardware guys:
A QFN or QFP on some kind of break out board that makes it breadboard/RadioShack/PCB compatible for around $20. No power supply... no other connectors of any kind. We are going to need one for the PropII anyway[noparse]:)[/noparse]