Re: configuring an Efinix T20

From	piglet <erichpwagner@hotmail.com>
Newsgroups	sci.electronics.design, comp.arch.fpga, comp.sys.raspberry.pi
Subject	Re: configuring an Efinix T20
Date	2024-09-09 20:02 +0000
Organization	A noiseless patient Spider
Message-ID	<vbnk8m$2hhvl$1@dont-email.me> (permalink)
References	<5h0ndj9c0cpc70eh6stoa5qi8371blq7nb@4ax.com> <vbhnef$190eu$1@dont-email.me> <h9todj9u2bs48i3itlgtorblj2buec7ios@4ax.com> <vbi62l$190eu$2@dont-email.me> <amhudj1mcq8uit59nbmm8d6j5erok8o0o1@4ax.com>

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john larkin <jl@650pot.com> wrote:
> 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?
> 
> 

Yes, that’s the one where they found the inductor “polarity” mattered!


-- 
piglet

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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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