Recent content by Rajinder

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    Voltage threshold issue

    Or are you saying set drive 1 and drive strength to 2mA and it will work i.e. meet requirements for VoH?
  2. R

    Voltage threshold issue

    I have seen that it is configurable as I/O pin. Cbus Drive 1 sets this to a high looking at table 3.7 Do we need to adjust the drive strength to 2mA? I can see all this. But can't see how this works with a internal pull up of 68K and pull down of 10K? Powered from 3.3V. I apologize but can't...
  3. R

    Voltage threshold issue

    Also the internal pull up from cbus3 is 68K. So if we have a 68K with a 10K pull down, vcc is 3.3V, this equates to around 0.5 V we are seeing with the scope. I am not sure how the 2mA for Voh for the gpio pin is configured. I presume via FTPROG utility. But would I then not have to adjust my...
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    Voltage threshold issue

    The pull down is hardwired with a 10K resistor. We are only using cbus3 to toggle a high level.
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    Voltage threshold issue

    I have measured the value of the internal pull up. Which is 66K. I think I have found the issue ViL for the STM32 is 0.43V, ViH is 1.26 V (minimum) . We are getting 0.5V on the boot0 pin i.e. indeterminate area. So it could be a logic 1 or 0. The 10K pull up changed to a100K results in units...
  6. R

    Voltage threshold issue

    Thanks for your reply. However, I can't understand how a voltage of 0.5V can he recognised as a logic 1 on the STM32, which has a minimum ViH of 1.26V.
  7. R

    Voltage threshold issue

    Yes sure.
  8. R

    Voltage threshold issue

    Hi all, We are trying to use a FT230x CBUS3 to control the BOOT status of a STM32F215. The boot pin of the STM32 is tied to 0V via a 10K pull down. The internal pull up of the FT device is used to toggle the boot pin. I have attached a diagram. We are seeing a voltage of 0.5V which does not...
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    Usb 2.0 component selection

    Thanks for sending the URL. Regarding the impedance, is this going to be a resistive loss at 100MHz. I am sorry but not sure. Can you help?
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    Usb 2.0 component selection

    Thanks for the reply. I can't see to open the link you sent for the discussion on the 1/10 wavelength. Also if my cable had a impedance of 50 ohms, then would the voltage divider not be 600/(600+50) x 5V = 4.6V? If the voltage divider affect is very low would that not prevent the circuit from...
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    Usb 2.0 component selection

    , I am using USB 2.0 full speed for a design. Power to the electronics is 5V from the USB, into a FTDI device ( which has an internal 3V3) regulator to power my electronics. I have a couple of questions, FTDi recommend a LC filter, they have also added an extra 10nF at the input and 4.7uF to...
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    Reset issue

    The supervisory will be a open drain type. However the FTDI is a GPIO which can be configured as an output or input. Hence my question about using a diode?
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    Reset issue

    Thanks, I will try using the open collector supervisory first with no diodes as pointed above in your feedback.
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    Reset issue

    Can I omit the diodes if I use an open drain supervisory device?
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    Reset issue

    I think based on what you mentioned. This is what I require? Would the forward voltage of the diodes matter, I think they might, are Schottky diodes best for this application?
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