Trying other ways to make chips

A project log for Shared Silicon

Silicon proven way to reduce the cost of integrated circuit manufacturing by collaboration

shaosSHAOS 12/05/2022 at 03:278 Comments

Currently I'm trying to jump to the last car of efabless train :)

- made a few test designs for TinyTapout that goes with efabless 130nm process as part of TT02;

- and also submitted 2 open source test designs to efabless 1st 180nm process that should go through GlobalFoundries

Nothing fancy, because everything is done through Verilog - you can actually draw your schematics in Wokwi but it's eventually converted to Verilog as well. Good thing is that self-made latches are translated to low level almost as is:

This is a Muller gate (or C-gate) and if it will work as intended on actual chip then it means async designs are very possible with this Yosys driven process :)


Yann Guidon / YGDES wrote 05/26/2023 at 10:57 point

I'll have to wait until I can get a tapeout that provides at least 30 direct IOs, or #YGREC8  won't be possible.

I already have the ceramic chip carriers :-P but no bonding machine.

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SHAOS wrote 05/26/2023 at 16:06 point

GF180 provides 16 inputs and 12 outputs (without need of reprogramming of on-board microcontroller) and you always can do multiplexing :)

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Yann Guidon / YGDES wrote 05/26/2023 at 16:08 point

can some of them be bidirectional ?

I'll need to know more :-P

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SHAOS wrote 05/26/2023 at 16:18 point

I think by re-programming of onboard RISC-V MCU you can add a few IOs and probably make some bidirectional - I need to learn more myself :)
For now I use simplest way possible - custom logic exists on the side and on-board MCU is not used.

UPDATE: Yes - all of them could be used as bidirectional! Look at
here 16 inputs and 12 outputs are hard-wired to be inputs and outputs, but those control bits could be driven by custom logic as well, so they could be generic IOs!

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SHAOS wrote 05/26/2023 at 16:37 point

output [37:0] io_oeb;

output [37:0] io_out;

input [37:0] io_in;

as you can see it's 38 IOs total, but some of them are used to control onboard MCU, so only 28 available to user by default, but it looks like user can re-program direction of them on the fly by setting/clearing io_oeb bits

This is how my 1st project connected to GP180 now:

user_module_348540666182107731 mod (
// all output enabled
assign io_oeb[23:16] = 8'b0;

and very similar but more IOs in 2nd project:

user_module_350175937959035475 mod (
// all output enabled
assign io_oeb[35:24] = 8'b0;

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SHAOS wrote 05/26/2023 at 04:36 point

GF180 designs should come in June 2023 :)

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matt venn wrote 12/05/2022 at 10:38 point


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SHAOS wrote 12/06/2022 at 03:24 point

Hi, Matt!
Thank you for TinyTapout :)
Looking forward to participate in TT03 ;)

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