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PostPosted: Sun Apr 22, 2018 9:02 pm 
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In my opinion, they're too expensive per cart.

The iCE40xx384s don't have enough I/O, even though they're otherwise cheap enough and have enough logic inside.

The iCE40xx1K parts are about $4, plus a few dimes for its boot ROM and two regulators. They're not 5V tolerant, but the cost of that translation is probably balanced out by cheaper 3V parallel NOR flash. Might be possible to justify it for MMC5-class stuff, but it's really the wrong place for anything less.

(Note: the $3 iCE40LP1K has way too few pins)


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PostPosted: Sun Apr 22, 2018 9:44 pm 
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zzo38 wrote:
Do you know how suitable iCE40 devices are?

In my original post I didn't elaborate much on higher density devices with 1k+ logic elements. If you have a good use/need for that much logic the iCE40 devices are comparable to Lattice MachXO2 & Altera max10 devices. Price and density wise they're all somewhat comparable, and you can avoid BGA packages with all of them. If you're looking for MMC5 scale hardware the iCE40-HX series would be a good fit as the 100-144pin TQFP packages are offered in 1k-2k LE options.


lidnariq wrote:
(Note: the $3 iCE40LP1K has way too few pins)

For a traditional design this is true. But if you want to get fancy and take advantage of the level shifters and actually make them work for you, the 39 i/o may just be enough. I've got a time multiplexed 'dual port' design I'm prototyping on right now that only requires 53 gpio and has full PPU/CPU bus decoding and 1MByte of ROM/RAM. While working on it I've recently realized some other tricks that might be able to be pulled off to get the i/o count down to 33 which would fit within the iCE5LP1K/2K/4K QFN-48 package that provides 39 io.

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PostPosted: Sun Apr 22, 2018 10:32 pm 
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infiniteneslives wrote:
lidnariq wrote:
(Note: the $3 iCE40LP1K has way too few pins)
For a traditional design this is true. But if you want to get fancy and take advantage of the level shifters and actually make them work for you, the 39 i/o may just be enough.
Sorry, I elided a lot of details. What I should have said was "Be careful that the thing you think is cheap actually has enough pins; there are iCE40LP1Ks that only have 16 pins and 10 I/O.

That said, my caveats about the iCE40xx384s appears to have been wrong; they are now(?) selling iCE40LP384-SG32 (QFN32) for a quite nice price, and it's a little I/O limited (17 to 21). Other iCE40LP384 parts with more I/O are available for not too much more money, but require dealing with BGA (and thus possibly with 4-layer boards)

iCEstorm even recently grew support for the small 384-cell ones.


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