Thoughts on Blackfin?

[dcarr]

I'm working on the design of a product that's using a lower-end Blackfin processor (no DRAM).  Normally I'd prefer to go with an ARM of some type, but the application has some heavy DSP requirements that seem to fit the Blackfin ISA very well.  It would likely require a 500MHz+ core to go the ARM route.

What positive and negative experiences have you had with the Blackfin line?  Are there gotchas out there waiting to be found?

The toolchain is bare-metal GCC.  The code leans pretty heavily on a few mixed C/ASM loops and DMA transfers in and out of SPORT/SPI interfaces.  Things are working so far, but I'm not in deep enough yet to feel warm and fuzzy.

Thanks,
David

[coppice]

The Blackfins looked really good 10 years ago, but the world is passing them by now. I think ADI treats them as legacy products. You can match their speed using general purpose devices which are cheaper and have better tools.

[EEVblog]

Blackfin is very popular in Chinese designs (seen in a ton of scopes and other test gear teardowns), presumably because of cost and design talent in China familiar with them.
Whether or not it better/cheap to go with something else for a particular design is entirely product specific.

[coppice]

Blackfin is very popular in Chinese designs (seen in a ton of scopes and other test gear teardowns), presumably because of cost and design talent in China familiar with them.
Whether or not it better/cheap to go with something else for a particular design is entirely product specific.

Blackfins were popular in China a few years ago, but people gradually stopped using them for new designs. Strangely, a few new Blackfin designs popped up recently, using some of the oldest chips in the range. I don't know if ADI are suddenly offering insane prices to stimulate that.

[diyaudio]

I'm working on the design of a product that's using a lower-end Blackfin processor (no DRAM).  Normally I'd prefer to go with an ARM of some type, but the application has some heavy DSP requirements that seem to fit the Blackfin ISA very well.  It would likely require a 500MHz+ core to go the ARM route.

What positive and negative experiences have you had with the Blackfin line?  Are there gotchas out there waiting to be found?

The toolchain is bare-metal GCC.  The code leans pretty heavily on a few mixed C/ASM loops and DMA transfers in and out of SPORT/SPI interfaces.  Things are working so far, but I'm not in deep enough yet to feel warm and fuzzy.

Thanks,
David

I think for fixed point processor there are better options, but don't underestimate the new series BF-6XX upwards its carrying a dual core 500MHz check out Finboard .. http://www.finboard.org/

I must agree there are lots of other choices,  maybe AD gives better deals around volume cost compared to other vendors, I noticed they have lower silicon errata and fantastic a tool-chain.
 




 

[krivx]

What would be recommended instead of Blackfin? I have seen it used it in 2015 products and the price, packages and tools are attractive for small-scale stuff (DIYer really)

[legacy]

The toolchain is bare-metal GCC

you had better (&best) switch to VisualDSP++ (even if EOL)

[rsjsouza]

What would be recommended instead of Blackfin? I have seen it used it in 2015 products and the price, packages and tools are attractive for small-scale stuff (DIYer really)

In my experience, For DIYer or low volume production the game changes. The price of the device itself is not as important as the availability of cheap development kits, IDEs, compilers and JTAG debuggers. Also, most of the general purpose and high end DSPs out there are packaged in BGA, which brings another hurdle to the process - that is the reason why some folks even use the development kit itself as the base of the product or prototype.

I am familiar with TI. Their C5500 DSPs are fixed point general purpose (something along the lines of the BF7xx) but with lower cost JTAG (a XDS100v2 can be had for $50~80, compared to ADZS-ICE-1000 $150), lower cost IDE (CCS can be used for free with XDS100v2) and development kit (a C5535 ezDSP stick is $99, but I couldn't find a dev kit for the BF7xx).

Moving to higher performance (and higher BGA density) you have the C6740 DSPs with floating point and a bunch of additional peripherals (SATA, Ethernet, etc.). Its kit is $195 and you can use the same JTAG and IDE as above.

Depending on the level of signal processing you are doing, I would also check the C2000 family. I love them because they have built-in flash, tons of real-time control perihperals (PWMs, etc), lower density packaging (including TQFP) and some even have floating point capabilities. The same JTAG and IDE as above can be used as well.

At last, carefully check the software dev kits (SDKs), libraries and RTOSes available and see what makes sense for your project. As with anything, the devil is on the details and be very thorough to check if the RTOS or SDK supports the perihperals you need for the device you chose - it is not uncommon to see a SDK that supports everything for the flagship product but leaves things undone for the lower cost devices.

[krivx]

What would be recommended instead of Blackfin? I have seen it used it in 2015 products and the price, packages and tools are attractive for small-scale stuff (DIYer really)

In my experience, For DIYer or low volume production the game changes. The price of the device itself is not as important as the availability of cheap development kits, IDEs, compilers and JTAG debuggers. Also, most of the general purpose and high end DSPs out there are packaged in BGA, which brings another hurdle to the process - that is the reason why some folks even use the development kit itself as the base of the product or prototype.

This is a big deciding factor. A huge advantage of Blackfin is that some parts are available in LQFP, I can get something working with hand soldering on cheap OSHpark boards. I'll take a look at the TI offerings, it looks like the C5000 can be had in LFQP.

These are the famous TMS320 series, right? Any reason why these would be considered more modern or more reliable than BF?

[Marco]

The Delfino launchpad someone pointed out on another thread seems good value (4 week delivery time though, it's popular).

[Kalvin]

What would be recommended instead of Blackfin? I have seen it used it in 2015 products and the price, packages and tools are attractive for small-scale stuff (DIYer really)

In my experience, For DIYer or low volume production the game changes. The price of the device itself is not as important as the availability of cheap development kits, IDEs, compilers and JTAG debuggers. Also, most of the general purpose and high end DSPs out there are packaged in BGA, which brings another hurdle to the process - that is the reason why some folks even use the development kit itself as the base of the product or prototype.

This is a big deciding factor. A huge advantage of Blackfin is that some parts are available in LQFP, I can get something working with hand soldering on cheap OSHpark boards. I'll take a look at the TI offerings, it looks like the C5000 can be had in LFQP.

These are the famous TMS320 series, right? Any reason why these would be considered more modern or more reliable than BF?

Also, it is worth looking at the TI 32-bit floating point and fixed point devices:

http://www.ti.com/lsds/ti/microcontrollers_16-bit_32-bit/c2000_performance/real-time_control/f2833x_f2837x/overview.page

http://www.ti.com/lsds/ti/microcontrollers_16-bit_32-bit/c2000_performance/real-time_control/f2802x_f2803x_f2806x/overview.page

http://www.ti.com/lsds/ti/microcontrollers_16-bit_32-bit/c2000_performance/overview.page

They are available in LQFP with quite nice set of on-chip peripherals.

The floating point unit is only single precision, so someone may prefer a 16MHz 8-bit AVR for high precision floating point calculations

[krivx]

What would be recommended instead of Blackfin? I have seen it used it in 2015 products and the price, packages and tools are attractive for small-scale stuff (DIYer really)

In my experience, For DIYer or low volume production the game changes. The price of the device itself is not as important as the availability of cheap development kits, IDEs, compilers and JTAG debuggers. Also, most of the general purpose and high end DSPs out there are packaged in BGA, which brings another hurdle to the process - that is the reason why some folks even use the development kit itself as the base of the product or prototype.

This is a big deciding factor. A huge advantage of Blackfin is that some parts are available in LQFP, I can get something working with hand soldering on cheap OSHpark boards. I'll take a look at the TI offerings, it looks like the C5000 can be had in LFQP.

These are the famous TMS320 series, right? Any reason why these would be considered more modern or more reliable than BF?

Tms320 family dates back to 20 years ago and are still updating till this day. The same for bf, not as historic as 320, but still old and being continuously improved.

For packaging, with a precision tweezets, a hot air gun and a pair of good eyes there is really no package that can not be hand prototyped. Actually I prefer bga or qfn over lqfp, because the huge amount of surface tension compared to self weight makes alignment much easier. With lqfn, soldering iron must be used to enforce alignment, while with qfn and bga I can keep with only hot air or oven. Soldering iron for me is just auxiliary tool, I don't use it nearly as frequently as hot air gun.

The issue is with small runs, if I want to sell a few dozen complete boards I would prefer not to have unpredictable failures. I have looked at these chips for use in audio effects pedals where the user will be stepping/stomping on the enclosure - I don't really want to trust a BGA package if I can help it. With a lqfp I can at least inspect every pin.

[rsjsouza]

These are the famous TMS320 series, right? Any reason why these would be considered more modern or more reliable than BF?

Yes, the TMS320 name designates everything DSP on the TI product line, and they date back to 1982 (TMS32010). Just like BF, which is a subset of AD's DSP offerings, the different families I mentioned above are also subsets of the TMS320 series.

Given you are interested in audio, I recall years ago I worked with the C6713 - a 300MHz floating point beast that supported I2S, S/PDIF and AC97 (my needs at the time). This one is also available in QFP.

One of the advantages of having a more powerful processor running the show is that you have a lot of flexibility - use the same HW for different products with different capabilities. This has the (huge) drawback of having a higher cost, but running a tight ship is only worth after the product is mature or the volumes require shaving all the extra cents.

The issue is with small runs, if I want to sell a few dozen complete boards I would prefer not to have unpredictable failures. I have looked at these chips for use in audio effects pedals where the user will be stepping/stomping on the enclosure - I don't really want to trust a BGA package if I can help it. With a lqfp I can at least inspect every pin.

That is a concern - if the assembler does not have BGA inspection machinery, that may bring some problems to small batches (that is why I have seen some folks use entire dev kits such as BeagleBone in their product). On the other hand, in my experience the smaller BGA packages (when compared to QFP counterparts) tend to suffer less mechanical stress, not only due to size but also most of their body is tightly "glued" to the PCB. Obviously that any failures cannot be easily inspected or detected with the naked eye, but if you carefully route your board to have vias under the BGA balls, you can still perform probing on the different device terminals.

[Macbeth]

Blackfin is very popular in Chinese designs (seen in a ton of scopes and other test gear teardowns), presumably because of cost and design talent in China familiar with them.
Whether or not it better/cheap to go with something else for a particular design is entirely product specific.

Rigol seems to be an exclusive Blackfin shop!

I was surprised to see my first firmware upgrade for my DM3058E 5.5 digit DMM labelled as a DSP upgrade. WTF? DSP in a simple DMM? why?

Indeed it uses the BF531. Scanning through the firmware for strings there are plenty of references to lwIP TCP/IP stack, lots of plaintext HTML, and the whole LDR file is in standard Blackfin LDR format bar the header id string and at the end of the LDR chain is more string data and at the end and a serial number and zero calibration.

So I had to recover my DM3058E after finding a simple way of bricking it accidentally and am now getting intimate with Blackfin. Successfully recovered it and also found my serial number data and calibration data and took a safe backup.

I fancy hacking this some more - it's much simpler than a scope or dsa! I'm guessing they used uClinux rather than raw assembler or any ADI licensed stuff!

Anyone recommend any dirty cheap BF53x boards from aliexpress or the like? I fancy rewriting my meters firmware just for the hell of it, but would like to practice and stage stuff first.

[marcopolo]

And why not a TMS320C6745 Fixed/Floating DSP running at 456 Mhz + 2 PRU at 200 Mhz with 320Kb of RAM  in a 176 pins LQFP case ?

[rsjsouza]

And why not a TMS320C6745 Fixed/Floating DSP running at 456 Mhz + 2 PRU at 200 Mhz with 320Kb of RAM  in a 176 pins LQFP case ?

Wow, that was really a surprise! Much more capable than the one I mentioned before (C6713) and there is even a slightly lower cost C6743 in LQFP as well...

[marcopolo]

And free samples available at TI 

[legacy]

This only applies to US, not sure about other countries.

applied to Europe/Italy too

[Macbeth]

I've just placed a sample order (UK). I do have a LTD company registered at my address though. No commercial website, but I do have a domain for email. 

[legacy]

I sent them a request through my university domain ( at polimi dot it ), and they denied my sample-order
then I sent them an other request through my company registered email, and they accepted the order 

[marcopolo]

I do have a LTD company registered at my address though. No commercial website, but I do have a domain for email. 

The same for me, I never had a problem with my orders.