4 ms·

I don't think ARM can displace AVR, mainly because ARM is expensive and weekend projects often doesn't require that much power for computation. ARM fits in neit

by llgrrl_ 15y ago

I don't think ARM can displace AVR, mainly because ARM is expensive and weekend projects often doesn't require that much power for computation. ARM fits in neither the simple projects category (AVR would do it more cheaply) nor complicated projects category (x86 would do it faster and more cheaply) for independent hackers. Plus, AVR now has a very friendly Arduino kit which is an important factor because of the sheer amount of support and community around it. Also, ARM is not standardlized, and is not very well supported with free software, which is another limitation which AVR doesn't have. I often follow hackaday.com -- it has tons of links to amazing projects and resources for the curious. I'm not doing AVR programming that much other than the microtouch kit, but I'm doing a little bit more on the TI's msp430 platform, mainly because I'm a student and thus, I'm cheap. Plus, TI's msp430 is insanely efficient, you can go very very low power and its language is C which is 'nicer' than the popular arduino pseudo-C code. For msp430 I often visit 43oh and refer to TI datasheet, they are often very very good.

kragen 15y ago
The Microtouch is using an ATMega32u4, which I think is this one: http://search.digikey.com/us/en/products/ATMEGA32U4-AU/ATMEGA32U4-AU-ND/1914602 http://search.digikey.com/us/en/products/ATMEGA32U4-AU/ATMEG..., which Digi-Key lists for US$3.79 each in quantity 25. An ARM alternative would be the LPC2103, such as http://search.digikey.com/us/en/products/LPC2103FBD48,151/568-2094-ND/857682 http://search.digikey.com/us/en/products/LPC2103FBD48,151/56..., US$4.95 in quantity 25. That's a real difference, but the Adafruit retail price of this device is US$70. But the ARM chip is, at least on paper, dramatically more capable: The AVR has an 8-bit ALU and runs up to 16MIPS (12MIPS in this case) and has 32K of Flash and 2.5K of RAM. The ARM has a 32-bit ALU, runs up to 70MIPS, has 32K of Flash, and 8K of RAM. So for boosting the price from US$70 to US$71 or US$72, it would seem that you get three times the RAM and six times the compute cycles. Newer ARM chips like the LPC1114 http://search.digikey.com/us/en/products/LPC1114FHN33%2F302:5/568-5152-ND/2507870 http://search.digikey.com/us/en/products/LPC1114FHN33%2F302:... are US$2.25, 50MHz (and I assume 50MIPS), 32K/8K, Cortex-M0. So there must be something I'm missing. What am I missing? Are the LPC2103 and LPC1114 a lot harder to integrate into existing designs? Is it that much harder to get ARM machine code out of GCC? Is the LPC very power-hungry? Does the LPC need some kind of expensive and complicated support circuitry? I'm out of my depth here. Help me out.
- kragen 15y ago
  I've been reading more of his blog. He's been doing some amazing things with the LPC111x family, like this offline Wikipedia reader http://rossum.posterous.com/wikipedia-homebrew-device-features-cortex-m0 http://rossum.posterous.com/wikipedia-homebrew-device-featur... and this video game console that generates composite video signals in software http://rossum.posterous.com/20131601 http://rossum.posterous.com/20131601. So I wonder if maybe he used the AVR instead of the ARM just because it was an earlier design.

by llgrrl_ 15y ago

kragen 15y ago

The Microtouch is using an ATMega32u4, which I think is this one: http://search.digikey.com/us/en/products/ATMEGA32U4-AU/ATMEGA32U4-AU-ND/1914602 http://search.digikey.com/us/en/products/ATMEGA32U4-AU/ATMEG..., which Digi-Key lists for US$3.79 each in quantity 25. An ARM alternative would be the LPC2103, such as http://search.digikey.com/us/en/products/LPC2103FBD48,151/568-2094-ND/857682 http://search.digikey.com/us/en/products/LPC2103FBD48,151/56..., US$4.95 in quantity 25. That's a real difference, but the Adafruit retail price of this device is US$70. But the ARM chip is, at least on paper, dramatically more capable: The AVR has an 8-bit ALU and runs up to 16MIPS (12MIPS in this case) and has 32K of Flash and 2.5K of RAM. The ARM has a 32-bit ALU, runs up to 70MIPS, has 32K of Flash, and 8K of RAM. So for boosting the price from US$70 to US$71 or US$72, it would seem that you get three times the RAM and six times the compute cycles. Newer ARM chips like the LPC1114 http://search.digikey.com/us/en/products/LPC1114FHN33%2F302:5/568-5152-ND/2507870 http://search.digikey.com/us/en/products/LPC1114FHN33%2F302:... are US$2.25, 50MHz (and I assume 50MIPS), 32K/8K, Cortex-M0. So there must be something I'm missing. What am I missing? Are the LPC2103 and LPC1114 a lot harder to integrate into existing designs? Is it that much harder to get ARM machine code out of GCC? Is the LPC very power-hungry? Does the LPC need some kind of expensive and complicated support circuitry? I'm out of my depth here. Help me out.

kragen 15y ago
I've been reading more of his blog. He's been doing some amazing things with the LPC111x family, like this offline Wikipedia reader http://rossum.posterous.com/wikipedia-homebrew-device-features-cortex-m0 http://rossum.posterous.com/wikipedia-homebrew-device-featur... and this video game console that generates composite video signals in software http://rossum.posterous.com/20131601 http://rossum.posterous.com/20131601. So I wonder if maybe he used the AVR instead of the ARM just because it was an earlier design.