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system76
Discussion: potential EC debugging/development tool
I'm not sure if this is the right place for this discussion, or if there is a better one, but I'm interested in trying a bit of a different approach to EC development and would like to gauge interest.
In particular, I'd like to develop a replacement for the ITE8587 in my galp4, probably based on the STM32L4R5 or similar, for a few reasons:
- I am pretty familiar with that MCU, and I think I may even be able to implement LPC using its DMA engine - otherwise, I'd probably switch to a smaller MCU such as something from the STM32L0 family and pair it with a very small ICE40 FPGA for LPC support
- It's a pretty capable MCU, but still very low power. I am also, in general, interested in any power optimization I can do to my system especially in suspend states (looking over the schematic, there are a lot of "freebie" improvements I have spotted already). Power optimization is a big part of what I do at work.
- There is a part from Maxim (MAX6621) that can be used to implement PECI.
- As an ARM Cortex-M processor, it can fairly easily support Rust
As a first step toward understanding more of the low-level messaging of the LPC bus, I've started working on a dev tool in the form of a m.2 3042 module that can be installed in the 3G module slot and includes an ICE40 FPGA in a configuration that should be compatible with the ICEstick dev tools, as well as the MAX6621 IC to experiment a bit with.
Is there any general interest in this concept, or even just in the m.2 FPGA board for dev use? My time is rather limited so I don't know how consistently I can work on it but if there is interest I'd be more motivated to continue on it, and to maintain a higher pace. By some very rough estimates, I think I could probably fabricate 20 of these boards for under $50/ea, less if people are comfortable hand-assembling them.
The hardware design is hosted here: https://github.com/mokus0/m2-ice40 The schematic is nearly complete for a first draft, but still needs review and FPGA I/O pin assignments, test points, etc.
The only place where LPC is accessible on the galp4 motherboard is where the IT8587E is soldered. It would have to be removed and replaced with a pin compatible replacement. I find it unlikely that this could be done with another chip.
The only place where LPC is accessible on the galp4 motherboard is where the IT8587E is soldered. It would have to be removed and replaced with a pin compatible replacement. I find it unlikely that this could be done with another chip.
My plan is to design a small PCB carrying the replacement circuit and solder it in place of the original EC. I am very comfortable with this level of rework.