I'm wondering what the physically smallest microcontrollers are, that aren't too crazy to program and that are amenable to hand soldering with normal SMT tools. I've found some of the ATtiny parts in 2x2mm packages. Is there anything else like that, preferably with a bit more code space and ram (these things have 512B code, 32B ram)? Is it difficult to work with those packages? A little larger is ok. The AVR instruction set is fairly nice. I'd consider the PIC10's to be crazy to program. I keep seeing claim that ARM devices are going to replace 8-bitters, but it seems to me that there will always be a need for really small stuff. Thanks.
Really tiny microcontrollers
Started by ●February 25, 2013
Reply by ●February 25, 20132013-02-25
On 02/25/2013 09:47 AM, Paul Rubin wrote:> I'm wondering what the physically smallest microcontrollers are, that > aren't too crazy to program and that are amenable to hand soldering with > normal SMT tools. I've found some of the ATtiny parts in 2x2mm > packages. Is there anything else like that, preferably with a bit more > code space and ram (these things have 512B code, 32B ram)? Is it > difficult to work with those packages? A little larger is ok. The AVR > instruction set is fairly nice. I'd consider the PIC10's to be crazy to > program. > > I keep seeing claim that ARM devices are going to replace 8-bitters, but > it seems to me that there will always be a need for really small stuff.The ARM Cortex M0 core in 90LP process is only 0.04 mm^2, so there's no physical reason why you couldn't put it in a tiny package. In fact, if you drop the hand soldering requirement, you can already get the LPC1102/1104 in a 2.2x2.36 mm BGA-16 package, including 32kB flash and 8kB of RAM.
Reply by ●February 25, 20132013-02-25
>>>>> Paul Rubin <no.email@nospam.invalid> writes:[...] > I've found some of the ATtiny parts in 2x2mm packages. Is there > anything else like that, preferably with a bit more code space and > ram (these things have 512B code, 32B ram)? ATtiny13A [1] has 1 KiB flash, 64 B SRAM. I was never interested in anything smaller than shrink SO-8's, though. [1] http://www.atmel.com/devices/ATTINY13A.aspx [...] -- FSF associate member #7257
Reply by ●February 25, 20132013-02-25
Arlet Ottens <usenet+5@c-scape.nl> writes:> The ARM Cortex M0 core in 90LP process is only 0.04 mm^2, so there's > no physical reason why you couldn't put it in a tiny package.For some reason they want to put these parts in packages with quite a few pins. For what I'm doing I'm happy with one a/d line and two or three gpio's, and could make do with less than that. So an 8-pin or maybe 6-pin package should be enough. I don't know why only the lowest-memory parts come in such small packages. I guess they think if you want more code space, you probably want to control a lot of stuff. They've lost track of how cheap the chips have gotten. If spending an extra dollar on a 4k part instead of an 1k part lets you develop the code a few days faster (by being less constrained about software tools and languages), for a low-quantity device it's well worth the slightly higher parts cost.> if you drop the hand soldering requirement, you can already get > the LPC1102/1104 in a 2.2x2.36 mm BGA-16 package, including 32kB flash > and 8kB of RAM.That's good to know about, and impressive. Is it possible to solder that part with a reflow oven and some tweezers, or does it need machine placement? I'm mostly a software guy and I've never messed with any parts that small, but I know some of the hardware hackers around here use toaster ovens for reflow soldering.
Reply by ●February 25, 20132013-02-25
Paul Rubin wrote:> Arlet Ottens <usenet+5@c-scape.nl> writes: > > The ARM Cortex M0 core in 90LP process is only 0.04 mm^2, so there's > > no physical reason why you couldn't put it in a tiny package. > > For some reason they want to put these parts in packages with quite a > few pins.Microchip's patents on really low pin count parts may be part of it the rest is likely a few more pins give the same part the ability to be sold into more applications. w..
Reply by ●February 25, 20132013-02-25
Paul Rubin <no.email@nospam.invalid> writes:> Arlet Ottens <usenet+5@c-scape.nl> writes: >> The ARM Cortex M0 core in 90LP process is only 0.04 mm^2, so there's >> no physical reason why you couldn't put it in a tiny package. > > For some reason they want to put these parts in packages with quite a > few pins. For what I'm doing I'm happy with one a/d line and two or > three gpio's, and could make do with less than that. So an 8-pin or > maybe 6-pin package should be enough. I don't know why only the > lowest-memory parts come in such small packages. I guess they think if > you want more code space, you probably want to control a lot of stuff. > They've lost track of how cheap the chips have gotten. If spending an > extra dollar on a 4k part instead of an 1k part lets you develop the > code a few days faster (by being less constrained about software tools > and languages), for a low-quantity device it's well worth the slightly > higher parts cost.Yes, the LPC were supposed to be "Low Pin Count" as I understand it. The LPC43xx has 100 pins as the lowest pin count package. -- John Devereux
Reply by ●February 25, 20132013-02-25
Paul Rubin <no.email@nospam.invalid> wrote: >That's good to know about, and impressive. Is it possible to solder >that part with a reflow oven and some tweezers, or does it need machine >placement? It is not a problem. I do all my prototype by hand-placement. But this is heplful: http://www.smtinspection.com/Mantis-Microscope/ >I'm mostly a software guy and I've never messed with any >parts that small, but I know some of the hardware hackers around here >use toaster ovens for reflow soldering. I prefer this: http://www.steinel.net/Professional-Heat-Guns/HG2310LCD Olaf
Reply by ●February 25, 20132013-02-25
On Mon, 25 Feb 2013 00:47:20 -0800, Paul Rubin wrote:> I'm wondering what the physically smallest microcontrollers are, that > aren't too crazy to program and that are amenable to hand soldering with > normal SMT tools. I've found some of the ATtiny parts in 2x2mm > packages. Is there anything else like that, preferably with a bit more > code space and ram (these things have 512B code, 32B ram)? Is it > difficult to work with those packages? A little larger is ok. The AVR > instruction set is fairly nice. I'd consider the PIC10's to be crazy to > program. > > I keep seeing claim that ARM devices are going to replace 8-bitters, but > it seems to me that there will always be a need for really small stuff.I suspect that there will be 8-bit processors for a good long while; it's just that they'll get pushed further and further down the food chain (while putting severe pressure on the top of whatever ecological niche is left for four-bit processors). I don't know if the tie-in between code space, ram and pins is egregious, or if that's really what the overall marked demands. I do know that I've been designing in a lot of chips lately that are selected for having the features I must have (including code space and RAM), and which end up having lots of unconnected pins. I suspect that for most applications having a few extra pins isn't a big cost, so the pressure on manufacturers to reduce the pin counts is mild. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Reply by ●February 25, 20132013-02-25
On Mon, 25 Feb 2013 00:47:20 -0800, Paul Rubin wrote:> I'm wondering what the physically smallest microcontrollers are, that > aren't too crazy to program and that are amenable to hand soldering with > normal SMT tools. I've found some of the ATtiny parts in 2x2mm > packages. Is there anything else like that, preferably with a bit more > code space and ram (these things have 512B code, 32B ram)? Is it > difficult to work with those packages? A little larger is ok. The AVR > instruction set is fairly nice. I'd consider the PIC10's to be crazy to > program. > > I keep seeing claim that ARM devices are going to replace 8-bitters, but > it seems to me that there will always be a need for really small stuff. > > Thanks.A quick search on DigiKey coughed up some 8-pin parts with 8kB of program memory (I didn't look beyond that), but unless you're willing to settle for a PIC there's not much to be had in 6-bit. The PIC instruction set is screwy, but at those sizes there's not much advantage to working in C anyway, and it makes more sense when you're doing your work in assembly than if you're staring, aghast, at the compiler output from C. -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Reply by ●February 25, 20132013-02-25
On 02/25/2013 06:32 PM, Tim Wescott wrote:> I suspect that for most applications having a few extra pins isn't a big > cost, so the pressure on manufacturers to reduce the pin counts is mild.Also, with devices such as the LPC1102, the package is only barely bigger than the silicon die itself, so putting 16 balls on the bottom keeps it smaller than putting 8 pins on the side.
