3 ms·

Microcontrollers aren't moving towards application level processors like the Raspberry Pi uses, they're moving towards low power ARM cores like the Cortex M0/M3

by leoedin 10y ago

Microcontrollers aren't moving towards application level processors like the Raspberry Pi uses, they're moving towards low power ARM cores like the Cortex M0/M3/M4. It's not clear to me why you'd choose an AVR for a new product unless you really, really needed a specific feature. Current generation ARM Cortex M0 devices are available at a similar cost and with significant performance gains, with the benefit that if you realise you need a more powerful core you can scale up to hundreds of MHz with effectively the same code base.

falcolas 10y ago
I'd love to read more about this microcontroller migration towards ARM - any hints on where to look?
- dragontamer 10y ago
  I dunno if its a 'major' migration, but NXP is basically doubling down on ARM-only architectures. Microchip / Atmel (same company now btw) are doing an "everything and anything" strategy. PIC, ATTiny, ATMega, UC3, AND ARM chips are available from them. It seems like the smaller 8-bit microcontrollers use less power and have better features for embedded engineers (ie: ADC converters, PWM, Real-time clocks, deeper sleep modes). While ARM has the general benefit of being much faster from a computational perspective. But if you want to read the voltage from a simple thermo-resistor and then output it on an I2C bus... I'm thinking a classic 8-bit AVR is going to be superior over any ARM. -------- I'm still seeing 8051 stuff pop up everywhere, and that thing was supposedly dead years ago.
- Matthias247 10y ago
  I don't have a single source about this. But some hints are: 10 years ago every µC manufacturer had it's own core and instruction set and basically sold them exclusively (maybe apart from some 8051 stuff). They were AVRs, PICs, V850, PPC, etc. Now when you look that the portfolio of those manufacturers they nearly all have at least one product with an ARM core in their portfolio. Some might even already stopped releasing new chips with their proprietary cores. Others have done that not yet but are planning to do this in the future (I've heard of at least one). Another hint is when you actually get in touch with a lot of complete product designs. The amount of ARM cores that you will see in there seems steadily to incline.
dragontamer 10y ago
I dunno of many Cortex M0+ devices that can source/sink 40mA like an AVR while only sipping 200uA (microAmps) like the AtMega328pb. That's active mode btw, AtMega328pb drops down to 1.3 uA in sleep mode. Cortex M0+ devices are "larger" than AVRs. You have more RAM, CPU power and unfortunately... complexity and power usage. I'm thinking a good example is the LPC811 from NXP: very good specs and it really shows how good ARM M0+ systems have become: http://www.nxp.com/documents/data_sheet/LPC81XM.pdf http://www.nxp.com/documents/data_sheet/LPC81XM.pdf But its still got an order of magnitude more power usage and complexity over AVR's AtMega328pb. The ATMega's "active" mode is comparable to the LPC811's "sleep" mode. Most of the LPC811's pins only can sink / source ~4mA, while the "biggest" pins can only sink / source 20mA. In contrast, all of the AtMega328pb pins can sink/source 40mA. Easily driving LEDs with only a resistor (instead of having to hook up a transistor or external buffer of some kind) The LPC811 also shows what happens to cheap ARM chips: they are missing ADC converters, PWM, Real-time Counters (or a deep-sleep mode that still keeps the 32kHz clock active). Sure, you can buy these externally... but the AVRs and PICs have superior integration. > It's not clear to me why you'd choose an AVR for a new product unless you really, really needed a specific feature. Running an LED with just a resistor on any pin is a pretty nifty feature IMO. ------------ The AtMega328pb is a "bigger" and more expensive part though. Perhaps its more "fair" to compare the LPC811 against the AtTiny44A (which is also $1.50ish). ATTiny44A has similar power specifications as the 328pb.

by leoedin 10y ago

falcolas 10y ago

I'd love to read more about this microcontroller migration towards ARM - any hints on where to look?

dragontamer 10y ago
I dunno if its a 'major' migration, but NXP is basically doubling down on ARM-only architectures. Microchip / Atmel (same company now btw) are doing an "everything and anything" strategy. PIC, ATTiny, ATMega, UC3, AND ARM chips are available from them. It seems like the smaller 8-bit microcontrollers use less power and have better features for embedded engineers (ie: ADC converters, PWM, Real-time clocks, deeper sleep modes). While ARM has the general benefit of being much faster from a computational perspective. But if you want to read the voltage from a simple thermo-resistor and then output it on an I2C bus... I'm thinking a classic 8-bit AVR is going to be superior over any ARM. -------- I'm still seeing 8051 stuff pop up everywhere, and that thing was supposedly dead years ago.
Matthias247 10y ago
I don't have a single source about this. But some hints are: 10 years ago every µC manufacturer had it's own core and instruction set and basically sold them exclusively (maybe apart from some 8051 stuff). They were AVRs, PICs, V850, PPC, etc. Now when you look that the portfolio of those manufacturers they nearly all have at least one product with an ARM core in their portfolio. Some might even already stopped releasing new chips with their proprietary cores. Others have done that not yet but are planning to do this in the future (I've heard of at least one). Another hint is when you actually get in touch with a lot of complete product designs. The amount of ARM cores that you will see in there seems steadily to incline.

dragontamer 10y ago

I dunno of many Cortex M0+ devices that can source/sink 40mA like an AVR while only sipping 200uA (microAmps) like the AtMega328pb. That's active mode btw, AtMega328pb drops down to 1.3 uA in sleep mode. Cortex M0+ devices are "larger" than AVRs. You have more RAM, CPU power and unfortunately... complexity and power usage. I'm thinking a good example is the LPC811 from NXP: very good specs and it really shows how good ARM M0+ systems have become: http://www.nxp.com/documents/data_sheet/LPC81XM.pdf http://www.nxp.com/documents/data_sheet/LPC81XM.pdf But its still got an order of magnitude more power usage and complexity over AVR's AtMega328pb. The ATMega's "active" mode is comparable to the LPC811's "sleep" mode. Most of the LPC811's pins only can sink / source ~4mA, while the "biggest" pins can only sink / source 20mA. In contrast, all of the AtMega328pb pins can sink/source 40mA. Easily driving LEDs with only a resistor (instead of having to hook up a transistor or external buffer of some kind) The LPC811 also shows what happens to cheap ARM chips: they are missing ADC converters, PWM, Real-time Counters (or a deep-sleep mode that still keeps the 32kHz clock active). Sure, you can buy these externally... but the AVRs and PICs have superior integration. > It's not clear to me why you'd choose an AVR for a new product unless you really, really needed a specific feature. Running an LED with just a resistor on any pin is a pretty nifty feature IMO. ------------ The AtMega328pb is a "bigger" and more expensive part though. Perhaps its more "fair" to compare the LPC811 against the AtTiny44A (which is also $1.50ish). ATTiny44A has similar power specifications as the 328pb.