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Forum Index : Microcontroller and PC projects : RPimite / RPiMMBasic
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| JohnS Guru  Joined: 18/11/2011 Location: United KingdomPosts: 3675 |
hmm, would need better names!! This is a thread to break rob's idea (using $20 RPi model A) off the PIC32MZ thread. The price is good. So is the large RAM. Not so good (leaving aside the "small" software porting effort): 1. few I/Os 2. quite high current 3. I/Os are not 5V-tolerant 4. only one USB so if a keyboard is added that makes none left 5. no ROM/flash memory Still, it's an interesting idea. Comments - c'mon rob I made a start :) John |
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G8JCF Guru Joined: 15/05/2014 Location: United KingdomPosts: 676 |
Hi John What about RPI A+, "RISC OS Pico" and BBC Basic (which permits inline ARM assembler)  
Peter The only Konstant is Change |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3675 |
I don't mind - except anything using BBC is likely to need explicit written permission from the obvious organisation, which I would not expect to be given. John |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 5918 |
I would rather stay clear of BBC Basic. Any MMBasic should be targeted to all the current Pi's. I would like a 'console' version but the main attraction of the Pi is it's video so a GUI version is the most practical. You could start with the existing IO (no analogue) and rely on a 'mite for analogue. You would then need to add TCPIP functions. There is also the Pi compute module which is designed for embedded applications. Jim VK7JH MMedit MMBasic Help |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9073 |
Yes, I have to say I like this idea. The Pi A+ board is extremely powerful bit of hardware for only $20 or so, and that to me looks like a perfect basis for a MaxiMite upgrade. You don't HAVE to have any GUI. The beauty of Linux is that you can have it boot to nothing more then a command-line. SORT-OF like the old days of Windows 95, when you could boot to DOS, and leave Windows unloaded, and call it with the WIN command from DOS if you wanted the GUI. I realise Linux is a bit different, but that is essentially the gist of it. Boot-up of the Pi would be the Linux kernel and command-line, and a script to load and execute the MMBASIC code. This would drop you back at a similar MMBASIC type command prompt as the current CMM does. The HDMI output would provide the graphics, but it need not be anything too fancy. Afterall, the beauty of the CMM is in it's simplicity. Just how much work would be needed to achieve that and port the MMBASIC code over - well, that is another story. If it was going to have to be a page-1 re-write, who the hell wants to do that.... Smoke makes things work. When the smoke gets out, it stops! |
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| hitsware Guru Joined: 23/11/2012 Location: United StatesPosts: 535 |
The name (BBC) may be misleading at this point. I've used the Windows version (BBC4W) for years. Wouldn't hurt to try. |
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| hitsware Guru Joined: 23/11/2012 Location: United StatesPosts: 535 |
> You don't HAVE to have any GUI. Who mentioned 'GUI' ? |
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| hitsware Guru Joined: 23/11/2012 Location: United StatesPosts: 535 |
edit : " BB4W " not " BBC4W " |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9073 |
Nobody. I am just saying, is all.
Many may think that cos the Pi has a glossy GUI, that you HAVE to have one to interface to it. Smoke makes things work. When the smoke gets out, it stops! |
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brucepython Regular Member  Joined: 19/06/2011 Location: AustraliaPosts: 64 |
The "BBC" version of BASIC was developed by Acorn Computers to run on their 6502-based machines. The "BBC" branding came about to accompany an intro to programming series the BBC developed (mostly for schools) in the early 1980s. With that selling well, Acorn put considerable resources into developing the ARM processor, rights to which were soon purchased by Apple, along with everything else. Understandably Apple's competitive approach to the education market didn't take Acorn's computers any further apart from a rather lacklustre series of ARM1 and ARM2-based desktops that trickled out in Acorn's final days. As the first user of one in Australia I was quite impressed by its speed compared to the newly-relased IBM clunker (and anything else around at the time) as it chucked Mandelbrot plots onto the screen at a hitherto unimaginable rate, even in interpreted BASIC. At least it gave me the chance to learn ARM assembler, though after 25 years of disuse I can't remember much about it now. 35 years after its release it's doubtful that the BBC retains much of a hold over BBC BASIC given that there are any number of emulators available for download. Maybe call it "BBC-compatible" BASIC. The development of the ARM was quite a feat given the extremely modest financial resources on hand. The first prototype chip worked perfectly, possibly a unique moment in software/firmware development. OTOH, they did have Sophie Wilson, who went on to inspire the development of later versions of the ARM with results that speak for themselves. |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2292 |
1. there is I2C and SPI - as i've just posted to another thread, there are devices that bridge from I2C to uarts. and similarly for all manner of other things like thermocouples, A/D converters, etc. yes, this does require the cost of an addon board. 2. the RPi A+ is surprisingly lean to run. 150mA at 5v seems to be largely agreed upon, which is probably similar to an existing colour maximite. the supply voltage range can be expanded using a us$1 switchmode converter from ebay china. the other RPi's (B, B+, 2) all consume much more current due to the ethernet and multiple usb ports (tied off a bridge that the A and A+ don't have). the original A and B also drew around 50% more power because of linear regulators. 3. an extremely valid point. this adds strength for an addon board to provide buffering. 4. a cheap hub can be plugged in, or do all expansion using the 40-pin connector. and as for extra storage... 5. what you plug into the the SD card slot effectively dictates the onboard flash available. a second SD card could be added to the addon board that also contains the I/O expansion devices from 1. and 3. rob :-) |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2292 |
offered without passing any judgement on merit: http://highcaffeinecontent.com/rpi/ it runs directly on the RPi hardware, no operating system in between. looks very much an early beta, but an interesting proof of concept. i'm guessing that the broadcom blob provides the application interface to video, audio, usb keyboard, and at least dumb digital access to the i/o pins. to date this seems to provide the best example i have seen of a RPi running an application but without any operating system underneath. cheers, rob :-) |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3675 |
The RPi Model A doesn't look to be available for $20 but rather a bit more, plus needs some I/O etc expansion. What's a more meaningful actual price for a workable set up? Maybe $30? I'm wondering what else can be had for whatever the figure is or near it. John |
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| srnet Senior Member  Joined: 08/08/2014 Location: United KingdomPosts: 164 |
Ah .... them was the days. At one point the little factory in S.Wales where I worked was making around 5000 of them a week. We caused worldwide shortages of several key bits of silicon, since we bought all avaialble supplies to meet the demand for the Beeb Micro. $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/ |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9073 |
Now, that's what I am talking about with the Pi A+, albeit with the MMBASIC instead of that BASIC, but if they can do it..... As to the I/O pins not being 5v tolerant, remember that many of the MicroMite pins are also not 5v tolerant. Some are, but many are not for the same reasons. An interface could be nothing more then a couple of resistors to form a potential divider with the 5v going in, and the PD dropping that 5v input to around 3v3 for the I/O pin. A couple of resistors means only a few cents per I/O pin you want to run at 5v. Smoke makes things work. When the smoke gets out, it stops! |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3675 |
Nobody's feeling that the RPi has too few I/Os? Not wanting more or different ones? I'm surprised. John |
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| hitsware Guru Joined: 23/11/2012 Location: United StatesPosts: 535 |
I can't believe anyone would even come close to using the ones available  |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2292 |
it is something that does trouble me - one of the strengths of the maximite and micromite is (in particular) the presence of analog inputs and (even more so with the micromite) a range of quite diverse functionality that are available 'out of the box' without needing any extra hardware. but then what is available may still be enough to fulfil the immediate desires of maybe 80% of users. experience in R&D has taught me that while it may be possible to please 80% of the customers within a reasonable budget, pleasing everyone in a single product creates a disproportionate expense. a suggestion would be to make up a list of all the things that a maximite can do, then a second list of all the things a micromite can do. i'm talking about analog input, read DS18B20 sensors, servo control, IR in/out, etc. it may be some can be achieved with clever software. cheers, rob :-) |
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