There is more than one way to skin a cat and there is getting to be a very large number of ways to design systems that need signal processing along with standard control processing. One of the MCU- like devices that are good at this is the Blackfin from ADI.
I had not paid a lot of attention to it in the past, but earlier this year I attended a seminar on it and realized that it is a pretty nice little chip in many ways. I tried joining the Blackfin Yahoo group only to find that it was overrun by spam (sound familiar?). So I started another one and have taken steps to preclude it from going the same route.
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If you have and interest in the Blackfin processor, you can discuss your issues and ask questions there. Being highly targeted, it should provide lots of good info.
I've been doing the designs with Blackfin since 2003 and still do, and I can tell you that Blackfin is same as crap as all other MCUs and CPUs. A tremendous list of the incredible bugs in the silicon, completely idiotic and unusable memory protection, poor set of peripherals, weak external bus shared between SRAM and other peripherals.
Yes, several things are good about it, however don't get over excited.
"Hallo freinds I am Babbadushman. I want 2 ask U a Q about 2+2=4. What does this mean? I need this urgent and immediately."
Am I already banned from there?
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
] Speaking of BlackFin, it was initially seen as the CPU for the ]cellphones. When it became apparent that they missed the market, ]Intel pulled out the plug, leaving ADI with the unripe project. ]ADI put the things together as they could, and released the ]obviously incomplete processor. Sadly enough, the original ]concept was appealing. Now ADI is pathetic in pushing ] BlackFin in all directions, including those where BlackFin ] doesn't fit (like the consumer video, for example).
So it's got low power consumption ? How would it be for a 2..4 AA-cell driven Ebook ? Or is the CPU power consumption irrelevant compared to a 80 * 20 char display ?
I don't recall for sure if uCliniux is ported, but I want to say yes. The power consumption is not especially low. The units I considered were about the same as one of the high end ARM CPUs, both in performance and power. They may have come out with some versions that are better on static power.
Although Blackfin consumes somewhat less power then the other DSPs, I wouldn't call it the low power processor.
The very minimum power consumption of Blackfin is at the order of 80mA at 3.3V. This is if the core is running at 24MHz and idling most of the time. At full speed, BlackFin burns about a couple of watts.
Kinda working. As good as the illustration of the possibility. If you want BlackFin to run with the speed of AVR, use ucLinux. uClinux is linux without MMU, which is nonsense indeed.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
has all information you need + active discussion groups (including a uClinux - subforum). I don't think there is any need for another discussion group.
One of my Blackfin projects (based on a '533) uses less power than that:
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I am not at liberty to divulge the actual numbers, but it appears that one's mileage varies on power consumption.
Hmmm, I have delivered a couple of solutions using uClinux for the Blackfin. I am not sure if it's ready for prime-time (i.e. ready to power something you could sell at Best Buy), but it is definitely good enough to deliver single-digit prototypes to customers or perhaps if you are making some sort of test equipment that is for the lab and not for consumer use. So I guess I agree with you there.
Hahaha! Quite a bit of an exaggeration, but the point is correct. gcc for the Blackfin is about 40% slower than ccblkfin (the ADI compiler), and linux adds some overhead that isn't there if you use your own OS (like I usually do).
I am not involved in the usual linux or OS religious wars, so I don't know if linux w/o an MMU is nonsense. I mean, is VDK without an MMU(*) retarded? Is any pre-rolled OS running on a chip without an MMU silly?
The reason I used uClinux was that the client wanted TCP/IP running over gigabit ethernet from their blackfin, and they needed it pronto. My analysis (given the time and $$ involved) was that the only way to achieve all the goals was to port the existing gigabit linux driver to uClinux for the Blackfin, and it worked great. All I had to do was to get the ethernet chip working, and from there TCP/IP was a done deal.
Plus since I had to follow the GPL, you all can benefit from my work on the gigabit driver (it's rolled into the base distribution now). Since then, ADI has taken it over and increased the performance of the driver since I last touched it. Sure wish they had been interested in the driver before I spent all those late nights in kernel panic :-)
--Keith
(*) BTW the Blackfin does have an MMU, just not one that gives the granularity needed for a port of the real linux kernel.
I was planning the BF-537 for the low power project, and I measured the actual power consumption that can be attained. There could be some +/- difference, however the ballpark is going to be as I cited.
By design, linux was meant for the 386 protected mode. A lot of the functionality of the linux core relies on the MMU. Linux without MMU is the perversion of the base concepts.
VDK is retarded regardless.
The dynamic memory management without MMU is unsafe and involves many tradeoffs. The memory protection is the other highly desirable feature of MMU. Blackfin has a rudimentary MMU which doesn't provide neither address translation nor a sensible mechanism for the memory protection. The exception handling of BlackFin is simply a nightmare: there is no sense in the way it is implemented, and there are the ugly bugs in the silicon in the addition to that.
We developed the proprietary RTOS for Blackfin, including the posix compliant FAT32 file system and TCP/IP stack over the BlackFin native MAC. At minimum, it can run from the bare 537-class chip using only the internal memories.
I could never understand the joys of the GPL.
Obviously they wanted to make the real MMU (look at all of those empty registers), however it didn't happen.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
So then what device/configuration would you advise for a black & white 80 char wide, probably 20 lines, reader from eg. CF, running from 2 to 4 rechargable AA cells & no-frills miminal cost ?
The task is stated very vaguely; it can be anything from as simple as PIC/AVR to as complex as iPod/TabletPC depending on what the device should be capable of.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
It starts from the belief that the 'one laptop per child' hyped-idea from MIT can't handle the lack of mains electricity in 3rd world locations.
So the 2 to 4 rechargable AA's need to give about 8 hours reading. I didn't yet find out about display power consumption, and a 'hi-volume used for other devices' display would be used. Of course if the display's consumption is significant then the CPU is less relevant. I guess a 8-bit CPU would do, except for the lack of ability to leaverage existing software, eg. uclinux.
Here's some ideas of required capabilities for the student/reader:
hyper link to random sections,
bookmark where I was last time,
bookmark the stuff/s that I want to show Joe & Jill..
cutNpaste ..........
search: where-else/if XYZ was mentioned........
embed(?sp) [simple] sketches in the text...posibly animated
... etc. ..your ideas/requirements...
So, I realise that the half second delay of low-power Epaper is a problem for eg. cutNpaste.
I'm thinking of a 5 or 10 finger-capacitive-pad input mouse-like/pointer.
Probably the starting decision must be the display ?
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