On Sunday, November 17, 2019 at 6:39:48 PM UTC-5, Paul Rubin wrote:
> Rick C <gnuarm.deletethisbit@gmail.com> writes:
> > Yes, I've also written my own processors for FPGAs. They can use a
> > fair amount of resources and potentially run slowly.
>
> Have you looked at Bernd Paysan's b16? It seems more resource efficient
> than e.g. a RISC-V softcore could possibly be.
>
> > Many of the FPGA devices I've used could barely support a CPU with
> > limited RAM. The biggest issue I fight now is package type.
>
> https://www.seeedstudio.com/Sipeed-Tang-Nano-FPGA-board-powered-by-GW1N-1-FPGA-p-4304.html
>
> I don't know how to identify the package from the photo on the above
> page, but the part has 72kbit of block ram, 1152 LUT-4's, 864
> flip-flops, 96k of flash, and from the board price, the part itself must
> be pretty cheap.
>
> Doc page here, but no idea what dev tools are needed:
>
> https://github.com/sipeed/Tang-Nano-Doc
Thanks for your references, but I am familiar with both Bernd's b16 and the Gowin devices. The Gowin devices were mentioned in my original post. None of the Gowin devices with hard CPUs are available in packages useful to me. The part on the Tang Nano board does not have enough FPGA capability or I/Os in the QN48 package and doesn't include a CPU at all. This part is intended for smaller applications. As I've already mentioned, I need at least the QN88 package.
I'm in touch with the Gowin US sales person. My potential volumes are a few thousand a year. I don't know what the price is for any given part since their distributors don't show any parts I am interested in. They want to discuss my needs, so I may know more about their road map later in the week if I can get with them by phone.
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Reply by Paul Rubin●November 17, 20192019-11-17
Rick C <gnuarm.deletethisbit@gmail.com> writes:
> Yes, I've also written my own processors for FPGAs. They can use a
> fair amount of resources and potentially run slowly.
Have you looked at Bernd Paysan's b16? It seems more resource efficient
than e.g. a RISC-V softcore could possibly be.
> Many of the FPGA devices I've used could barely support a CPU with
> limited RAM. The biggest issue I fight now is package type.
On Sunday, November 17, 2019 at 9:21:04 AM UTC-5, John Speth wrote:
> On 11/16/2019 4:13 PM, Rick C wrote:
> > My holy grail has always been a simple CPU combined with an smallish FPGA. There are a few out there, very few, but none of them are available in appropriate packages and inexpensive.
> >
>
> You could use an FPGA and load a "soft" core of your choosing. It
> probably will not be as cost effective if you find a hard core
> alternative that fits your needs.
Yes, I've also written my own processors for FPGAs. They can use a fair amount of resources and potentially run slowly. Many of the FPGA devices I've used could barely support a CPU with limited RAM. The biggest issue I fight now is package type. I'm loath to try to lay out fine pitch BGAs when the only reason I would use them it because it is so hard to find FPGAs in anything else.
The two ideal packages for much of my work are the QFN88 and VQFP100, the latter being what I'm using on a board in current production (actually in production for 11 years now). The QFN88 is quite a bit smaller, but in the end may not be better because of the large thermal pad using all the room for vias under the part.
Keeping all the processing on chip reduces the need for I/O and keeps the speeds up.
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Reply by John Speth●November 17, 20192019-11-17
On 11/16/2019 4:13 PM, Rick C wrote:
> My holy grail has always been a simple CPU combined with an smallish FPGA. There are a few out there, very few, but none of them are available in appropriate packages and inexpensive.
>
You could use an FPGA and load a "soft" core of your choosing. It
probably will not be as cost effective if you find a hard core
alternative that fits your needs.
JJS
Reply by Rick C●November 16, 20192019-11-16
On Saturday, November 16, 2019 at 7:13:14 PM UTC-5, Rick C wrote:
> My holy grail has always been a simple CPU combined with an smallish FPGA. There are a few out there, very few, but none of them are available in appropriate packages and inexpensive.
>
> I've found a couple of Chinese startups that seem to have some interesting devices. AGM has the AG6K, a 6k LUT with 250 MHz ARM in a QFP100, pretty much the perfect part. Trouble is I can't tell if this company is real. Or maybe they are targeting customers buying millions with nothing to offer the smaller users.
>
> Another is by Gowin. They actually make several. They have options for extra memory along with an ARM CPU and 2 or 4 kLUTs. But they fall down on the packaging. They offer a 48QFN and a couple of other larger packages, but nothing suitable. They use the 88QFN and 100QFP, but not for the ARM version. They even have a version with a Bluetooth stack, but for some reason that uses an ARC processor (not that it's a problem) and still comes up very short in the packaging/IO count. Gowin seems a bit more real, but still hard to find anyone selling their product line.
>
> The docs from both companies are not so easy to glean info from. I guess that goes with the territory of start ups.
While making sure I had my facts right I kinda got off on a tangent. My point is that the AGM devices include an ARM as well as some of the Gowin parts. But the Gowin Bluetooth device uses an ARC EM4
at 24MHz. I've not seem much of the ARC processors. Are they yet another embedded processor that is pretty much as good as any? Certainly 24 MHz isn't very impressive, but I guess it's good enough for a Bluetooth stack.
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Reply by Rick C●November 16, 20192019-11-16
My holy grail has always been a simple CPU combined with an smallish FPGA. There are a few out there, very few, but none of them are available in appropriate packages and inexpensive.
I've found a couple of Chinese startups that seem to have some interesting devices. AGM has the AG6K, a 6k LUT with 250 MHz ARM in a QFP100, pretty much the perfect part. Trouble is I can't tell if this company is real. Or maybe they are targeting customers buying millions with nothing to offer the smaller users.
Another is by Gowin. They actually make several. They have options for extra memory along with an ARM CPU and 2 or 4 kLUTs. But they fall down on the packaging. They offer a 48QFN and a couple of other larger packages, but nothing suitable. They use the 88QFN and 100QFP, but not for the ARM version. They even have a version with a Bluetooth stack, but for some reason that uses an ARC processor (not that it's a problem) and still comes up very short in the packaging/IO count. Gowin seems a bit more real, but still hard to find anyone selling their product line.
The docs from both companies are not so easy to glean info from. I guess that goes with the territory of start ups.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209