When I google for the PIC 18F models, not much shows up. I only find catalogs and datasheets, and not the amazing amount of hobby and student projects that are available on the web for the 16F series.
Is there a good reason for that, or is that family just too new?
What do people here think about the 18F? Is it an interesting controller or just more of the same?
S.
I think most student and hobyist projects do well by using the simpler 16F. You get to concentrate on the peripherals. The 18F is for more complex projects requiring lots more software support, hence the support for a larger stack for easier high-level language support.
I think that Atmels Mega AVR series is taking most of the market away from Microchip's 18F series. For performance and high-level language support the AVR is hard to beat.
regards, Johnny.
Isn't being new a good reason ? The Flash version of PIC18xx did not show up until 2002, so in uC terms it is very new. [Their dsPIC has been talked about since 2001, but has only just started sampling.]
Contrast that with the PIC16C family, which has had over 15 years shipping in OTP (longer in ROM )
So, it's really no surprise the PIC16 series shows up much more than the PIC18 series, in the hobby/student arena.
The PIC18 has larger opcodes, so was able to extend the opcode reach of the PIC16, but it has also landed in a more crowded market segment.
-jg
If it ain't broke why fix it ?! As far as a manufacturer... In this highly competitive market, it can actaully be cheaper,therefore higher profit, to go with what you know and works, than spend big bucks reengineering getting the so called 'latest and greatest' chip to do the job. Same is true about NOT flipping over to another manufacturers chip. I shudder at the amount of time( and money!) lost reengineeering a product only to find out the new chip wasn't available in quantity when the time came. As a hobbyist... Again, if it ain't broke, don't change. I've found the F84 and F877 to be fine for all the projects around here.Over 15 years of new toys and gadgets and never had a true requirement to change chips. Course I don't find PIC ASM hard,either.Heck 35 instructions isn't that difficult...compared to the
120+ for the Z80 back in the '70s.Jay
16F was good but 18F is great. I replaced a 16F77 and two 93C86 EEPROMs with one 18F452 and it paid for itself. A lot of the wrinkles have been ironed out, there's a hardware multiplier, parts are cheap enough, bigger stack, flexible clocking, quite a few reasons to switch.
Why not so popular yet? People have tooled up for the 16 series and (unlike AVR) there are no free compilers for PICs.
Regards, Mike.
I have purchased my C compilers for the PICs, but I had no idea that there is no free version available. Is this really true?
Jon
I opened up the latest issue of Circuit Cellar and there's a project using an
18F.
I think some of it is momentum, and some is evolution overtaking that market segment, and some of it is just the general ugliness of programming a PIC.
Last I looked, the 18F442 was like $4.20 ea. in low qty. Philips has an ARM based micro for around $5 these days that seems to have a lot of momentum, TI MSP430 seems popular, as is AVR. All of these have decent core speeds and a version of gcc which helps the hobby market.
Not really. Not in my book, anyway.
Jon
No, it's too expensive on a bang-per-buck level, and there's no real momentum behind it.
It's got less wrong with it than the PIC17, but it's a hell of a lot more expensive than the PIC16. And it's harder to program and needs more code space than AVRs or HC12s. And it's certainly pricier than the Motorola.
There are also some badly-handled incompatibilities (you lose a chunk of Access RAM) between the 18 and the 18F, IIRC (or is that only the
18Fs with CAN controllers - I forget...)Microchip's low-end customers keep buying the baby PICs, their attempts to move upmarket with the 17, 18 and dsPIC (30) just aren't succeeding.
(Personally, I think they should license the ARM7 core and wrap that up in typical Microchip packaging with a narrow data bus - the gate count is probably comparable to the PIC18!)
pete
If you have a proven product shipping, why change ?
There are many ways companies spin the stats, that's why we have around
4 claiming to all be #1!If you look at the PIC volumes, and work back the Average selling price, Microchip has one of the lowest ASPs in the 8 bit area, of just under $1 - so clearly their volumes are heavily skewed to the bottom end. From a revenue viewpoint, it is different, and ISTR seeing ~50% of Microchips revenues are now in Flash uC.
Atmel are now doing that, and going down as small as 32KF ARMs in tqfp48. Must make for interesting politics between their AVR and FlashARM groups :)
Microchip are well behind on the release of their dsPIC, and it has to wait for the tool flows, resource, and training to develop. Assuming the dsPIC hits critical mass, where does that leave the PIC18?
With Microcontrollers today, the 4 P's [Price, Peripherals, Package & Process ] matter more than the core, and if those are equal, a Multisourced core will win out.
-jg
I don't think they're trying to compete with each other. dsPIC is being aimed at the low-end fixed-point DSP market. Which is also getting crowded....
Microchip really has two things going for it - packaging and Keeloq.
pete
The Hitech C compiler seems to come close to meeting the C90 standard, depending on your definition of "close". As has been pointed out to me in this newsgroup not too long ago, it is not fully compliant. But in practice, it is much closer to standards compliance than I ever dreamed of expecting for a PIC compiler.
Too expensive? A company for which I've done some consulting switched from the PIC16F877 to the PIC18F452, at least partially at my urging. I thought it would be a hard sell, even though we desperately needed the additional memory. As it turned out, though, the PIC18F452 costs *less* than the PIC16F877.
I've recently found the same to be the case when comparing some of the smaller PICs as well. The PIC18 parts seem to be fairly aggressively priced.
As far as I can tell, they seem to be selling quite a lot of PIC18 parts. Which chips are commonly used by hobbyists is not a very convincing metric of which chips are selling in the highest volumes.
Does it permit reentrant code, or does it still treat auto variables like statics? In which case it ain't C....
IAR is probably the nearest to "standard".
pete
From a hobby perspective, it looks to me like that isn't really the case. Take a look at
These are all one-off prices in Australian dollars.20MHz PIC16F877 is about $12. a 40MHz PIC18F4320 does more, and is less then ten bucks. On the lower end, the very widely used (but obsolete) PIC16F84A-20/P goes for $6.50 - the PIC18F1320-I/P sels for just under $6.
I don't see how its the case. Sure, only having 35 instructions on the PIC16 seems appealing to raw beginners. but the extra instructions are realy useful.
Also, the _big_ dvantage on the PIC18 is there is no paging, and pretty much no banking. The banks are larger, and the 'access bank' generally means you don't have to change banks to access SFR's. You can access a file from any bank with MOVFF.
I'd buy that. I'd like to program ARMs in a low pin DIP package :-)
cheers,
Al
The 48-pin Philips LPC210x ARM is available on a DIL40 module.
Leon
Since the call stack is strictly limited and there is no way to move items on or off it, re-entrancy seems inherently impossible, barring an interpreter.
This isn't true for a PIC18fxxx, there are PUSH and POP instructions. I think the stack is typically only 32 levels deep though.
Al
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