Lattice iCE40HX1K FPGA

[Freya]

The modulator chips have been ok for a while, albeit from china. I bought several large batches in 2018 &2021 and have enough for about another 75 Hedghogs. PIC18F26K22T-I_SS are tricky to get, suppliers are backorder until may or june unless it gets pushed on again.

[`FRANK.C]

Hi Jeffrey
I haven't tried to order any of the modulators in years.
Searching  AliExpress I see some listed but I think Stephen is best placed to answer that question.
All I can do is to have a video out on it so an external modulator can be fitted if necessary.

The iCE40HX4k-TQ144 is a much larger and from memory I think it has 2 PLL's. RS appear to have the only stock. Mouser, DigiKey and Farnell have no stock.
The pin out is different to the iCE40HX1k-TQ144

It is a about Altera there tools are in a different league to the Lattice ones. They are so much easier to use.
The Lattice tools I find are a lot more work to use and possibly dumber.

Frank

Edit: Stephen replied while I was typing.

[ppppenguin]

Not so cheap but not too bad: https://uk.rs-online.com/web/p/fpga-deve...-_-1840485
Available from more than one distributor. Amply powerful FPGA. Not much accessible IO.

The Arty looks like a powerful development tool but too expensive to inlcude in a low cost converter: https://www.xilinx.com/products/boards-a...lj76y.html

[Freya]

All I can do is to have a video out on it so an external modulator can be fitted if necessary.

Is that due to FPGA limitations ? it would be handy to have an internal IDC header so a modulator block could be plugged in with a different firmware, or just a miniaturised VOL

[`FRANK.C]

Hi Jeffrey
Some nice boards there. A lot of the larger FPGA's seam to be coming in BGA or similar packages which makes soldering difficult.

Hi Stephen
No it would be only for if the modulator chips were no longer available.
The FPGA will have no impact on it.

There are potentially a couple of ways that the modulators and video decoder. could be programmed.
This FPGA has a feature that makes booting from different program images stored in the flash memory easy.
It has a cold boot option which allows the boot image to be selected with 2 of the FPGA pins. It will then boot from this image at power up or when the FPGA is reset.
It has also a warm boot option which allows the current program to select a image and trigger the FPGA to boot from it.

The warm boot could be use to boot from an image that contains a bit banger to program the modulators. When it has completed programming the modulators it could then load the image that contains the converter.

A cold boot uses no extra logic but a warm boot would.

The PIC is doing the programming of the video decoder now. I think I will most likely to keep it to do that and the modulators.

Frank

[ppppenguin]

If you have a microprocessor it's usually easier to let that do any "bit banging" programming of other chips. Darryl did the Aurora without a uP so all the bit banging had to be done in the FPGA.

Booting multiple images on-the-fly to do different jobs is really last resort stuff. I've done it once in a design. My excuse was I was very new to FPGAs and had chosen devices that were too small. All the booting had to be hand fettled in a uP, with data stored in UV EPROM. No luxuries to make booting different images easier.

If you're going to use a BGA then it's best to buy it pre-assembled on a carrier board. It is possible to DIY with a hot air workstation.

[Nick]

DIY BGA reflow is fraught with potential pitfalls, specifically with unreliable contacts.

Commercial, these are x-rayed for QC - there's no reasonable way for an amateur to do this.

[Mike Watterson]

Home BGA mounting is really a last resort for prototypes or repair of your own gear. Buying a pre-mounted module or commercial subcontract is needed?

Also I agree FPGA + mpu is the best route unless the FPGA is merely a prototype for an ASIC.

[ppppenguin]

There are plenty of MPU cores for FPGAs. It's not something I've ever looked at but in the Xilinx world things start with the tiny Picoblaze, something I suspect would be good for control jobs such as bit-banging I2C chips or doing Timecode. Goes all the way up to ARM cores and presumably RISC-V too. Plus peripheral cores and hardware support such as for ethernet, USB etc.

I always used an external MPU in my designs. Normally with somebody else programming it. I doubt I'll be doing any new designs now.

[Mike Watterson]

There are MPUs on FPGA by FPGA design (uses a lot of area/resource, things like 8051, basic PIC etc) and secondly more expensive FPGAs that have an actual physical core as would be on the standalone mpu such as an ARM Cortex. I suspect Jeffery means the 2nd kind.