Migrating from PIC18 to ARM: which MCU to choose?
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From: rickman on 26 Jul 2010 09:46 On Jul 22, 2:41 pm, Stimpy <rjmvxlvzj...(a)mailinator.com> wrote: > Thanks to everyone for all the good advice. After doing more digging, > here's where I'm at: > > Luminary Micro (Texas Instruments) Stellaris LM3S2110: analog > comparators are nice, but the timer seems to be lacking the output > compare feature. I really need the set-on-match and clear-on-match > functions (with interrupt) to generate a pulse train with accurate > timing. I really don't want to bit-bang this since the timing > requirements are fairly tight. Unless there's a way to do this that's > not obvious from my quick glance at the datasheet, I don't think I can > use this part. All the Stellaris 2000, 5000, and 8000 seem to share > the same crippled timer peripheral. > > Cypress PSoC5: the built-in PLD would be nice to offload some of the > pulse generation stuff but otherwise it looks like overkill for this > product. Pricing and availability seem questionable as well. I'd also > be a little worried designing in such a specialized part, especially > from a single source. It would certainly save a bunch of PCB space > right now but having to substitute this later on would be a nightmare. > > Freescale Kinetis: doesn't appear to be available yet. > > Nuvoton: Pricing is excellent! But to get the CAN controller I would > need the NUC130 which isn't in production yet. The Canadian > distributor (Arrow) doesn't show ANY NUC1xx parts in their catalog > either. As an aside, Nuvoton appears to be a division of Winbond and I > still have a bad aftertaste in my mouth from Winbond's buggy IO > controllers in the early 90s. > > STM32: The STM32F105R8 looks really good, it even has a DAC and the > DMA can work on both the SPI and the DAC! The 20mA sink current on the > IO ports is nice too. I'm almost sold on this one but one year lead > time?? Please tell me that was a joke. > > NXP LPC1700 series: Fewer features than the STM32 but slightly lower > price and probably better availability. > > Regarding the lack of EEPROM on these devices, I realize I can use > part of the FLASH to hold data but typical usage requires 5-10 writes > per day and I'm not sure about the endurance on the FLASH; the PIC's > EEPROM is rated at 100K writes minimum. Also this product doesn't have > a battery and it can (and does) get unplugged at any time. On the PIC, > a write is only 4ms and losing power during a write will only lose one > byte which is not a big deal. Losing an entire sector of FLASH would > be catastrophic. An external EEPROM is not an issue, since they now > come in SOT-23 packages for pennies each. > > I guess it's really come down to STM32 vs. LPC1700. > > Has anybody had any experience with either or both in terms of > development, integration, and availability? I didn't realize Nuvoton is a part of Winbond. My customer is having to discontinue a board because the Winbond CODEC part is being discontinued. Of course that happens to any company, but I get the impression this was not expected. Of course this is working out for me, but I wouldn't design in any of their parts just because they don't give me any reason to have confidence in their supply channels. Who are their distys anyway, anyone major? BTW, I don't see Atmel in this list. They are a major ARM vendor and should not be discounted. The SAM7 parts are still very viable devices and the SAM3 parts are the hot, new products in their ARM lineup. I was very glad to learn about the Kinetis. It looks like a great chip even if it is a bit early to get details on. The low power may be the best on the market for a process with these capabilities, the analog sounds excellent and it has fantastic comms with USB On-The-Go Full speed and up to six UARTs not to mention a wide variety of packages. An M4 core (with DSP instructions) may make it the fastest Cortex MCU on the market when it arrives. But that all depends on when it arrives. Of course, the cost is another issue we won't know about for some time too. "The first five general-purpose Kinetis MCU families are expected to sample in the second half of 2010 with production planned for early 2011" I don't have a calibration on Freescale. This could mean design in parts for production Jan 1 (Lattice model) or it could mean wait for 12 more months before even bothering to ask about them (Cypress model). I will say, goofy name... "Kinetis". But at least you won't have a lot of false hits in Google... Rick
From: -jg on 26 Jul 2010 16:12 On Jul 27, 1:46 am, rickman <gnu...(a)gmail.com> wrote: > I don't have a calibration on > Freescale. You might want to factor in the bragging rights bantam-posturing going on between NXP and Freescale. Both have M4's coming, and so both Marketing Depts are trying to claim to be first. NXP demo'd early silicon, then Freescale release partial info, and real hard info on production dates will not be real, until the errata on the engineering samples is out... Then there is the errata on the core itself ;) -jg
From: Stimpy on 26 Jul 2010 16:57 On Jul 26, 8:46 am, rickman <gnu...(a)gmail.com> wrote: > BTW, I don't see Atmel in this list. They are a major ARM vendor and > should not be discounted. The SAM7 parts are still very viable > devices and the SAM3 parts are the hot, new products in their ARM > lineup. You're right, I completely forgot about Atmel. The SAM3 looks quite good, it also has the DAC and DMA and SPI and probably the most flexible timer / waveform generator that I've seen so far. The butilt- in ROM bootloader is nice too, although not very useful for this product. Now I've checked Digikey, Mouser, Arrow, Future, Farnell and other than the development kit, no parts in stock anywhere. Are these things actually available yet? If not, then I think I'll go with the STM32. Now the question is which toolchain/JTAG to go with. I don't really feel like mucking around with the DIY Eclipse/GCC/GDB/OpenOCD/Wiggler solution and things like Keil, IAR, Greenhills, and Tasking are well outside the budget. This leaves me with one of the "packaged" GCC offerings like Rowley, Raisonance, Hitex, iSystem, Atollic, Aiji. Does anybody have any experience with any of those? After reading a few past discussions on here it looks like Rowley is a good choice, Raisonance is OK but slow, and the Hitex IDE isn't all that great.
From: linnix on 26 Jul 2010 19:03 On Jul 26, 1:57 pm, Stimpy <rjmvxlvzj...(a)mailinator.com> wrote: > On Jul 26, 8:46 am, rickman <gnu...(a)gmail.com> wrote: > > > BTW, I don't see Atmel in this list. They are a major ARM vendor and > > should not be discounted. The SAM7 parts are still very viable > > devices and the SAM3 parts are the hot, new products in their ARM > > lineup. > > You're right, I completely forgot about Atmel. The SAM3 looks quite > good, it also has the DAC and DMA and SPI and probably the most > flexible timer / waveform generator that I've seen so far. The butilt- > in ROM bootloader is nice too, although not very useful for this > product. Now I've checked Digikey, Mouser, Arrow, Future, Farnell and > other than the development kit, no parts in stock anywhere. Are these > things actually available yet? If not, then I think I'll go with the > STM32. > > Now the question is which toolchain/JTAG to go with. I don't really > feel like mucking around with the DIY Eclipse/GCC/GDB/OpenOCD/Wiggler > solution and things like Keil, IAR, Greenhills, and Tasking are well > outside the budget. This leaves me with one of the "packaged" GCC > offerings like Rowley, Raisonance, Hitex, iSystem, Atollic, Aiji. Code_red for NXP is good. > Does anybody have any experience with any of those? After reading a > few past discussions on here it looks like Rowley is a good choice, > Raisonance is OK but slow, and the Hitex IDE isn't all that great. We have been discussing my specs in another thread. Since you want CAN and I don't, we might end up with different chips. However, many of the issues are common between us. Regarding programming tool chains. NXP LPC is the best with USB Mass Storage emulation. Namely, flash appears as USB drive. The chip would be real simple to program. USB to SWD bridges are available to most; so, it is the second best. My spec: 30 I/O <= uC && uC <= 48 pins Flash I/O Cost Comment STM32F103C8T6A 64K 37 5.00 ~CAN ~LIN ATSAM3S1AA-AU 64K 34 4.30 LPC1343FBD48,151 32K 40 3.20 Flash *= 2 MCF51JM64VLD 64K 33 3.00 PIC24FJ64GB004-I/PT 64K 33 3.00 NUC120LD3AN 128K 31 2 (?)
From: Leon on 27 Jul 2010 19:47
On 26 July, 21:57, Stimpy <rjmvxlvzj...(a)mailinator.com> wrote: > On Jul 26, 8:46 am, rickman <gnu...(a)gmail.com> wrote: > > > BTW, I don't see Atmel in this list. They are a major ARM vendor and > > should not be discounted. The SAM7 parts are still very viable > > devices and the SAM3 parts are the hot, new products in their ARM > > lineup. > > You're right, I completely forgot about Atmel. The SAM3 looks quite > good, it also has the DAC and DMA and SPI and probably the most > flexible timer / waveform generator that I've seen so far. The butilt- > in ROM bootloader is nice too, although not very useful for this > product. Now I've checked Digikey, Mouser, Arrow, Future, Farnell and > other than the development kit, no parts in stock anywhere. Are these > things actually available yet? If not, then I think I'll go with the > STM32. Atmel is having serious availability problems right across their range. Leon |