Quote from: NebulaMiner on November 25, 2022, 05:00:35 PM

Quote from: Skot on November 25, 2022, 03:31:36 PM

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Can you please push a PDF of the schematic so I can do a review.

yes, here you go; https://github.com/skot/bitaxe/blob/max_v2/bitaxeMax.pdf

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About the BM1393 voltage regulation, do you plan a voltage tuning from the MCU ?

Yes, that will be new for bitaxeMax v2. I'm using the Maxim DS4432U+ current DAC with the TPS40305 -> BM1397 core voltage adjustment will be over I2C. note on the current schematic there are a couple feedback resistor values TBD.

Here is my Schematic review :
- I see DS4432U+ OUT0 being used for TPS40305 control, but does the OUT1 being used somewhere ? (if not use, better not creating a signal out of the package to give ambiguity...)
- where the 5V is generated ? I see +3V3 (U11), 1V8 (U5) and 0V8 (U6) being generated from 5V, and BM1397 VDD (alias of TPS40305 VOUT) being generated from VIN_M (the monitored VIN), but nowhere the 5V beoing generated...
- on the ESP, I think you inverted TX/RX, please double check it
- can you add pin header and TP for debug purpose on the 3V3 RX/TX/RST, (additionnaly to J3), and add also I2C SDA/SCL signal on this debug pin header ?
- can you use an optional (with a serial 0R resistor) signal from a CLK_OUT of the ESP (pin 13/14/34/33/32 up to you) going to the BM1397 CLKI instead of the U1 one. I may want to try later if MCU can generate this clock by SW so we have control on the hashrate of the BM1397...
- on the BM1397 you pulled down BI (with R4) are you sure it will not being used ? on BM1385 datasheet it is noted as a Busy Input (internal schmit trugger and pull down). Maybe you can link it to a GPIO of the MCU, we will see later if needed. (and add the 3V3 signal to the debug pin header too).
- for the voltage level translators (U2/U3/U4), I used to use TSX0104 in my previous design, it is easy to use because bidirectionnal. Did you consider them ?
- for EMC2101, the ALTER#/TACH pin can be configured as input (TACH monitor to mesure Fan RPM) or output (ALERT# signal to trigger an IRQ on MCU when special temp/tach conditons are met). I see more value having an ALERT# signal from it to the MCU to trigger an interrupt for Temperature Critical exceeded (with hysteresis to deassert the signal). The FAN RPM is not very usefull for us. Also EMC2101 porpose a Look-up Table of 8 stages so we can control by hardware FAN speed accoding to BM1397 internal temperature. Maybe what you can do, is link the EMC2101 ALERT#/TACH pin to a MCU GPIO, and the FAN TACH to another MCU GPIO (be careful of voltage level here), and SW will be able to configure EMC2101 in TACH reading for some seconds, by propagating the FAN signal, then switch back to ALERT interrupt for a longer period (1h ?). So most of the time we use Interrupt monitor, and only once in a while do a fAN RPM measurement for UI needs...
- it would be usedfull to have the BM1397 VDD on a ESP ADC input to measure the BM voltage
- it would be usefull to have the TPS40305 PGOOD linked to a ESP GPIO to know if Power is Good

I checked in an update to the schematic on the max_v2 branch with all of these changes. I'm still a little iffy on the level shifting for the interface to CLKI and the fan ALERT.