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Type: Posts; User: harvie

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  1. Closed: Re: Configuring ICE40 FPGA directly from ESP32 uC rather than using dedicated flash I

    I've just checked the datasheet and the pinout section states the SPI configuration pins are shared and can be reused as GPIO after configuration. So that's perfect for me... (i don't need to occupy...
  2. Closed: Re: Configuring ICE40 FPGA directly from ESP32 uC rather than using dedicated flash I

    Yes. I was hoping that uC in Slave SPI mode can pretend it's a flash IC to make things easy :-)

    BTW does the FPGA need the SPI to be online after the configuration was done? Can i reuse the SPI...
  3. Closed: Configuring ICE40 FPGA directly from ESP32 uC rather than using dedicated flash IC

    Hello. I am working on project based around Espressif ESP32 uC and Lattice ICE40 FPGA. FPGA will do some heavy lifting and handle several buses, while providing uC with preprocessed data over SPI.
    ...
  4. [SOLVED]Closed: Re: MAX232 alternative with more lines in single package

    Ha! Thanks for pointing this out. Actualy i've went through MAX24x chips before, but the landing pages that google found showed MAX232 block diagram instead, which confused me. But now when i...
  5. [SOLVED]Closed: MAX232 alternative with more lines in single package

    Hello, i am working on FPGA project with 32 duplex serial lines and i need to do conversion to RS232 voltage levels.
    MAX232 can handle 4 lines, which would mean to use 16 pieces of MAX232 IC (only...
  6. Closed: Re: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    Haha so true. I've already started looking. I like ICE40 and ECP5, they seem to have nice opensource toolchain available (yosys+nextpnr + icestorm or trellis)....
  7. Closed: Re: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    Didn't knew about this possibility. I will surely look it up. I don't think it's possible on all the devices that i need to connect, but i might be able to use it to simplify my daisychaining...
  8. Closed: Re: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    I think i will run daisy chained serial line through couple of uCs with at least 4 to10 times higher baudrate than the baudrate i need to handle at endpoints. I will inject some kind of custom packet...
  9. Closed: Re: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    Well... I am not designing the endpoints. These are given. I just need to aggregate them on single device. That's the way things are in computer world. Servers, routers and switches have serial...
  10. Closed: Re: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    Thanks for cool tips with the FPGA! Sounds like interresting project. I've never designed with such chips and it seems to me there's bit of learning curve to overcome at the beginning... I totaly...
  11. Closed: Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?

    Hello,
    i have approximately 32 Linux servers with 115200 baud serial console and i would like to connect all of them to single ESP32. While keeping things relatively scalable.
    I know that first i...
  12. Closed: Re: shunt 24V rail to reference voltage using opamp?

    https://en.wikipedia.org/wiki/EBUS_(serial_buses)#Physical_layer

    This is TX circuit. RX circuit is however quite similar, it also has voltage divider and opamp with optocoupler anode at its...
  13. Closed: Re: shunt 24V rail to reference voltage using opamp?

    I did not invented this communication protocol. I just need to interface with it. This is very common for heating boiler control. But there are several variants with different voltage levels and i...
  14. Closed: Re: shunt 24V rail to reference voltage using opamp?

    Thanks for reply. I've mentioned that i use LM358 opamp instead of LM393 for this very reason... This was the first problem i've encountered. Didn't updated the schematic yet..
  15. Closed: shunt 24V rail to reference voltage using opamp?

    Hello,
    i have following circuit:

    156231


    "VBUS" is 24V bus limited to 200mA, it serves for both power and data transfer.
    If i want to transmit logic HIGH i leave it like that. If i want to...
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    Closed: Re: Doppler "radar" motion detector design

    It depends, but generally yes. This guy experimented with it: https://www.youtube.com/watch?v=9WiJJgIi3W0
  17. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    @KlausST Yes. you are true. There is thermal drift. I initialy noticed just the high frequency noise and didn't realized there is thermal drift. So i just went back and checked again.

    When i heat...
  18. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Just did similar test with HX711 module at maximum gain of 128

    Got step around 0.0015 uV, with input pins shorted the noise was causing fluctuation of +-0.1 uV

    So i am pretty confident that you...
  19. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Ok, so i've been doing some tests with Arduino ATMega 2560.

    I've used ADMUX = 0b10001011 which means following:

    internal 1.1V reference
    adc0 negative, adc1 positive
    200x gain

    It got me...
  20. Closed: Re: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Does it mean that when i set AREF to 40mV, i will get approximately the same behavior as HX711?

    Also the atmel has some kind of gain setting, i am not sure how that applies to AREF.
  21. Closed: Attiny85/Atmega32u4 internal differential ADC to replace HX711?

    Hello,
    i've recently found that Attiny85 and Atmega32u4 come with differential ADC capabilities.

    I was messing with load cells (strain gauge wheatstone bridges) used as weight/force sensors....
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    Closed: Charge Pump Whistle (ST662/MAX662)

    Hello,
    i've designed circuit using ST662 charge pump IC (5V to 12V; 30mA; 400kHz; Clone of MAX662) and the first prototype PCB we've assembled produces slight audible whistling under load. (We are...
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    Closed: Re: Doppler "radar" motion detector design

    I've found datasheet of RCWL-0516 module:
    https://img.filipeflop.com/files/download/Datasheet_rcwl-0516.pdf
    Updated version: https://github.com/jdesbonnet/RCWL-0516

    It seems to explain...
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    Closed: Re: Doppler "radar" motion detector design

    Yes. Antenna is left side. It's double sided and usualy has some funny shape. IIRC this one has some kind of circle on the other side.

    These modules usualy range between 2 to 30 GHz, depending on...
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    Closed: Re: Doppler "radar" motion detector design

    Cool. Thanks for info. I was worried if the output analog signal has enough amplitude (voltage) to be detected by internal ADCs of common uC (eg. atmega).
    I don't need direction sensitivity, but it...
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