Quote from: Skot on November 27, 2022, 08:53:13 PM

Quote from: NebulaMiner on November 27, 2022, 08:50:14 AM

Great, did another check :
- for the CLKI signal directly on the ESP, please add a 0R (or a 33R as it is a clock) serial resistor to disconnect this signal by HW.

there is one already, it's on the BM1397 sheet.

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- on J3, maybe better to put 1V8 on this debug connector because all signals are on 1,8V level (and now the 3V3 is available on J6)

good idea. added.

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- maybe better using the 4th TSX0104 line for the CLKI signal instead of BI, and put BI on the voltage divider ? BI is low freq signal. Waht do you think about this ? I have the feeling high freq signal are better ont the TSX0104 (otherwise we should better use voltage divider for all signal from ESP to BM).

I added a SN74AXC1T45 for level shifting the BM1397 clock. If we're going to try this we should prolly do it right. the SN74AXC1T45 has a max freq of 500 Mbps (and is in stock!)

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- on the Fan design, I understad you plan to use a 5V FAN directly powered by our input VIN,
* Firstly, Fan usually generate lot of noise, we should consider filtering this noise.

I looked around for some thoughts on this and didn't find more more than "it's complicated". I think we might have to try this out and see where the noise is coming from. Then we can add some bypass caps, filters, etc.

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* Secondly, we will control this fan with a 3V3 level PWM, and the 5V TACH signal is directly on the EMC2101 pin. Maybe better using a TSX0102 for level converting 3V3/5V these 2 signals.
* Finnaly, as for this dual signal we are not sure yet of the final usage, I would do a more modular (optioal) HW design using 0R resistors. For exemple:
a/ 1 signal from the FAN TACH_3V3 (from J4 after going through TSX0102) connected to a dedicated ESP GPIO (with the 0R resistor so we can unconnect it)
b/ 1 signal from the FAN TACH_3V3 (from J4 after going through TSX0102) connected to the EMC2101 ALERT#/TACH pin (with another 0R resistor so we can unconnect it)
c/ 1 signal from the EMC2101 ALERT#/TACH pin connected to a dedicated ESP GPIO (diffeent from a/) (also with a 0R resistor so we can unconnect it)
this way we can choose by HW (some 0R resistor) the logic we want to try during the development phase.

These kinds of level conversions are exactly what the EMC2101 is supposed to solve. My hope in using it is that the ESP32 can control the fan and read the BM1397 temperature easily over I2C, without having to generate any specific timing signals.

OK with current Schematic and your justifications.

Another idea : can you add a couple of ESP GPIO with a pullup and a dual pin header to ground, so we can use jumper to switch SW into specific mode (for exemple, mining on a pool or with a local node RPC connection,... we will discuss these mode later when designing the SW)