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Re: configuring an Efinix T20

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On Sat, 7 Sep 2024 19:29:41 +0100, John R Walliker
<jrwalliker@gmail.com> wrote:

>On 07/09/2024 16:58, john larkin wrote:
>> On Sat, 7 Sep 2024 15:19:59 +0100, John R Walliker
>> <jrwalliker@gmail.com> wrote:
>> 
>>> On 06/09/2024 23:50, john larkin wrote:
>>>>
>>>> I'm planning to use a Raspberry Pi RP2040 processor chip to configure
>>>> and then talk to an Efinix T20-FG256 FPGA.
>>>>
>>>> Has anyone done this, or at least configured a T20 from a
>>>> microprocessor?
>>>>
>>>> The RP2040 only has 30 GPIO pins, and many are dedicated to other
>>>> stuff, so we want to share a lot of things on one giant SPI bus,
>>>> including the FPGA config and then an SPI port on the FPGA to read and
>>>> write registers.
>>>>
>>>> It looks like four of the T20 config pins need pullups. I wonder why
>>>> their guidelines show four separate resistors. Why not one resistor?
>>>> Why have resistors at all?
>>>>
>>>> SS_N needs a pulldown. Why not ground it?
>>>>
>>>> https://www.dropbox.com/scl/fi/x0gvvwqg42vhryu6610ve/Efinix_Config_1.jpg?rlkey=udy24brtumvdzfd2sp4l6yhwf&raw=1
>>>>
>>>>
>>>> It's always a moment to celebrate when a "config done" LED lights up.
>>>>
>>>> I could easily get this wrong, so it would be great if I posted some
>>>> schematics and notes and someone could eyeball them for me.
>>>
>>> If you need some more i/o pins, why not use the RP2350B?  They
>>> definitely exist - I have one in front of me:
>>> https://shop.pimoroni.com/products/pga2350?variant=42092629229651
>>>
>>> John
>> 
>> It only has two more package pins, as I recall. How many GPIOs?
>
>No.  The RP2354B has 24 more package pins and 18 more GPIOs than
>the RP2040.
>
>Its an 80-pin package with 48 GPIOs.

I was thinking about the RP2350, which has 60 pins. That's the chip on
the Pico 2.

I didn't even know that there was another small chip, the 2354B. That
might be the next step for our product line, in a year or two after
the new chips are debugged and available in quantity.

The 2350 data sheet is 1349 pages, possibly a world record.

I can't immediately find a data sheet for the 2354B.

>
>> It's new and a bit buggy and not widely available, so we'll stick with
>> the 2040. The only upsides are the higher clock rate and the faster
>> floats, which aren't critical in the product line that we are
>> developing now.
>
>Yes, there are some bugs.  The most critical is probably the one
>relating to on-chip pull-downs, but it can be solved with external
>resistors.  The ADC is improved.  There are more and better
>i/o state machines.  There is a lot more on-chip RAM and there
>will soon be the option of flash in the same package.
>There may not be production quantities of the RP2354B readily
>available yet, but there are certainly some around for prototypes.
>As I mentioned, I have one.

Does the 2350 have a switching regulator on-chip? Microns away from
the ADC?

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Thread

configuring an Efinix T20 john larkin <jl@650pot.com> - 2024-09-06 15:50 -0700
  Re: configuring an Efinix T20 John R Walliker <jrwalliker@gmail.com> - 2024-09-07 15:19 +0100
    Re: configuring an Efinix T20 john larkin <jlarkin_highland_tech> - 2024-09-07 08:58 -0700
      Re: configuring an Efinix T20 John R Walliker <jrwalliker@gmail.com> - 2024-09-07 19:29 +0100
        Re: configuring an Efinix T20 john larkin <jl@650pot.com> - 2024-09-09 12:20 -0700
          Re: configuring an Efinix T20 piglet <erichpwagner@hotmail.com> - 2024-09-09 20:02 +0000
            Re: configuring an Efinix T20 john larkin <jl@650pot.com> - 2024-09-09 14:17 -0700
  Re: configuring an Efinix T20 Lasse Langwadt <llc@fonz.dk> - 2024-09-12 00:44 +0200

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