Migrating from PIC18 to ARM: which MCU to choose?
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From: Stimpy on 22 Jul 2010 14:41 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?
From: -jg on 22 Jul 2010 17:13 On Jul 23, 1:41 am, rickman <gnu...(a)gmail.com> wrote: > > > Or, I see the new Nuvoton series, have just flipped into Stock, at Nu > > Horizonshttp://www.nuvoton.com/hq/enu/ProductAndSales/ProductLines/Industrial... > > > NUC100LE3AN NUVOTON 128KF 16KR QFP48 $2.5250 > > NUC100RE3AN NUVOTON 128KF 16KR QFP64 $2.7875 > > NUC120LE3AN NUVOTON 128KF 16KR QFP48 USB $2.7875 > > NUC120RE3AN NUVOTON 128KF 16KR QFP64 USB $2.9625 > > NUC120VD2AN NUVOTON 64KF 8KR QFO100 USB $2.7875 > > > These are 5V (wide supply range), and I see they do have Analog > > Comparators too :) > > > Eval PCBs look well priced too... > > > NUMICRO-SDK NUVOTON TECH CORP AMERICA Development Tools > > $43.7500 > > NUTINY-SDK-120 NUVOTON TECH CORP AMERICA Development Tools > > $19.0000 > > > Signs of a product manager, who knows what they are doing ? > > Sort of interesting, I hadn't heard of them before. A lot of their > parts are only in sampling stutas[sic]. But their prices are right! > I'm not sure I believe all their claims of parts in production. > Checking the NUC120LC1AN I can't even find it listed at either NuHo or > Arrow. Only some part numbers are released (I think 5?) > You can buy the SDK, but I can't even find a brochure on it! > Technically speaking, I see that the I/Os are only 5 volt tolerant > when powered by 5 volts. The power consumption is not so great > either. It will be interesting to see what application these parts > find. Where did you find the 'only 5V tolerant' IO specs on the MUC1xx family ? The Data sheet I'm reading, gives Ioh at 5V/2.7V/2.5V and whilst it does not have a I-V graph, itt looks like I'd expect a 5V-driven port to behave ? Port SCH shows VDD to the MOSFETS. NUC1xx Data sheets are here http://www.nuvoton.com/NuvotonMOSS/Community/ProductInfo.aspx?tp_GUID=d8297c69-7fbf-4c6c-b797-bcdd8ece8fc6 Development tools are here (I see now with photos, and Buy-links.) http://www.nuvoton.com/NuvotonMOSS/Community/ProductInfo.aspx?tp_GUID=403a9c50-52c2-4463-9057-2595190602c5 -jg
From: linnix on 22 Jul 2010 19:08 > 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. I agree. This is very interesting to watch, several months from now. > > 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. You get this joke from many companies for at least some of their parts. > 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. Perhaps you can slave a small PIC or AVR for the EEPROM and timers. They are more established for such functions. > > 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? SO, it's M3 (STM32) vs. M0 (LPC1700). I think M0 would be more popular down the line.
From: Michael Kellett on 23 Jul 2010 03:07 "Stimpy" <rjmvxlvzjqwi(a)mailinator.com> wrote in message news:9dca3a88-6146-4148-9684-57961b4b44cd(a)k39g2000yqb.googlegroups.com... > 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 can only talk about STM32 - I've just never used the NXP ARMs. Tools: I use the fully paid for Keil toolset but for small projects (<32k) you may be able to use the free version (check for terms and conditions). ST have a very cheap (�17.50) debugging interface. There are lots of free/open-source tools for any ARM part but expect to do a fair bit of work to get them going. Availability: For small quantities, Farnel list 53 STM32s of which 43 are in stock - you might not get exactly the part you want but you should be able to get close. (They have 115 of the STM32F105R8T6). For large numbers you will have issues with everyone. Development: ST have a quite comprehensive and reasonably documented peripheral control library which will get you going quickly. It's slow and a bit bloated so you may not want it in high volume, small memory applications but it seems to work (mostly). (FYI I think the Luminary support code is better but we're not talking about them now......) I've had no trouble getting the DMA, SPI, UARTS, ADC etc to work OK. The I2C peripheral is a bit messy and the support code is poor but can be worked round. I have no connection with ST other than as a customer but I have an interest in promoting the STM32 because the more they sell the cheaper they will get :-) Michael Kellett
From: linnix on 23 Jul 2010 13:00
> > 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 can only talk about STM32 - I've just never used the NXP ARMs. I have the Luminary Micro (LM3s811) with Keil and the LPCXpresso (LPC1114) with Code_Red (Gcc-arm port). But I am not too happy with both build-in USB debugging links. In the process of separating the LPC1114 (I need to try a LPC1111), I blew-up the board. I was going to get the LPCXpresso with LPC1343 (USB enabled), but the NUC120 seems more interesting. The separate USB-SWD Nuvoton link is more appropriate for my development. > Availability: For small quantities, Farnel list 53 STM32s of which 43 are in > stock - you might not get exactly the part you want but you should be able > to get close. (They have 115 of the STM32F105R8T6). For large numbers you > will have issues with everyone. LPC1343 is around $2.50 in 1Ku (1800 available at Digikey) NUC120 could be below $2 in 1Ku (too early to tell) We will stock at least 6 months of supply anyway, once we decide to use the chip. > > I have no connection with ST other than as a customer but I have an interest > in promoting the STM32 because the more they sell the cheaper they will get > :-) I have no connection with any chip manufacturer. I just use whatever is appropriate (usually, most cost effective one). |