November 30, 2022, 03:09:43 pm

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81
ESP32 / Re: ESP32-POE-ISO temperature
Last post by LubOlimex - November 11, 2022, 04:09:38 pm
R41 is required to maintain power signature (MPS). Refer to:

https://www.ti.com/lit/ds/symlink/tps2376.pdf?ts=1668174991211

What is the PSE equipment in your setup? Is it compliant with IEEE 802.3af (or newer)?

82
ESP32 / Re: ESP32-POE-ISO temperature
Last post by Drjaymz - November 11, 2022, 01:11:39 pm
Quote from: Drjaymz on November 11, 2022, 11:55:37 amI will remove R41 and measure the temps again and see how long it is before it glitches.

sitrep, with R41 removed its been up and running and has stabilized at about 35C which is a lot better than 90C and I would consider it ok to use in an enclosure now.

Another 'bug' I found was that the PG pin(6) from U2 should be pulled high.  If not then you might find that nearby transients could shutdown the DC-DC converter.

The DC-DC converter is perfectly fine at 0.5A from a 50V source, but its limitation window is a package temperature of 80C according to the datasheet.  Without R41 heating it up it doesn't get that warm at all, it should be better than 75% efficient in this circuit.
83
ST / Re: STM32-H407 I2C program not...
Last post by itisnt - November 11, 2022, 12:21:35 pm
I recompiled a lot, but i did not change the linker file, Makefile or anything else.

Hm, i am afraid i have to create a GCC/Makefile based I2C example with the GD Libs witch works, then i can compare what is different.

I you have some skeleton or template for the GD32-H407 with the 12MHz Osc and GCC and the GD32 libs, or know where i could find one, that would be awesome.

Daniel
84
ST / Re: STM32-H407 I2C program not...
Last post by LubOlimex - November 11, 2022, 11:57:00 am
Could be. On a side note, we had to re-compile the test examples we used here, I think there was some memory handling difference that required it.
85
ESP32 / Re: ESP32-POE-ISO temperature
Last post by Drjaymz - November 11, 2022, 11:55:37 am
Mine is getting too hot.  I'm measuring 50V and looking at the schematic, that is across R41 which is 4k7. At 50V thats over half a watt.

I am not sure why R41 exists.  But I think its one of a host of fudges to attempt to deal with glitching that this board design seems to have been plagued with looking at the revision changes.  I think its there to discharge C27 and soak up any transients.

Half a watt is easily within that resistor's capability, a hot resistor isn't going to fail.  I just put a thermocouple on mind and its 126C - half of that heat is soaking into the ground plane to which one end is soldered.

Unfortunately, because of the layout it heats up C26 and C27 and will cause them to fail and there's a couple of posts of exactly that type of failure and that will happen as soon as you enclose the design.  105c capacitors or not, remember at 105c their life is 1000hrs.

I will remove R41 and measure the temps again and see how long it is before it glitches.
86
ST / Re: STM32-H407 I2C program not...
Last post by itisnt - November 11, 2022, 11:45:07 am
Thanks,

That was also my first thought, but if you read the datasheet, you will see that ST has I2C1, I2C2 and I2C3 but GD has I2C0, I2C1 and I2C2

So if i take I2C2 in my STM32 based program it takes the registers which are I2C1 in GD and that should match for PF0 / PF1. Or am i wrong ?

And i see a reaction on SDA (PF1) on the oscilloscope. Maybe something with the different clock setups are different on GD ?

Daniel
87
ESP32 / Re: ESP-PoE-ISO - not getting ...
Last post by Drjaymz - November 11, 2022, 11:44:39 am
My work around for now is to:

  Serial.print("info: Ethernet connecting ");

  int timeout = 0;

  while (!ETH.localIP()[0] && timeout < 20)
  {
    delay(500);
    Serial.print(".");
    timeout++;
  }
  Serial.print(" Connected\n");

So this looks to see when the first IP byte is not 0 and then we're connected.

The message callbacks are not working deeper in the framework because the ETH.linkup() is still false when we're connected.

So, with this board, or the latest framework or something - the example doesn't work.
88
ST / Re: STM32-H407 I2C program not...
Last post by LubOlimex - November 11, 2022, 11:27:33 am
Comparing the datasheets it appears PF0 and PF1 are different I2C numbers. In STM32 it is I2C2, in GD32 it is I2C1.

You would need edit and to re-compile. Or search for the I2C1 at another location at the GD32 board - seems like PC9/PA8 and other places  :)

The datasheet for the GD chip can be found here:

https://gd32mcu.com/data/documents/datasheet/GD32F407xx_Datasheet_Rev2.5.pdf

The datasheet for the STM32 chip can be found here:

https://www.st.com/resource/en/datasheet/dm00037051.pdf

89
ESP32 / Re: MOD-RS232 Example
Last post by LubOlimex - November 11, 2022, 10:27:21 am
Well, you might need to consult with the documentation of the scanner and what is the format it sends. Can you share a screenshot of the gibberish you got, upload the picture somewhere online and post the link here.
90
ESP32 / Re: Powering through Lipo batt...
Last post by LubOlimex - November 11, 2022, 10:24:20 am
First you need to set the hardware to enable "Battery Measurement".

By default the function "Battery Measurement" is disabled by the state of an SMT jumper. The jumper "BAT/BUT1" is responsible for "Battery Measurement". This is done because the function uses one GPIO/ADC pin and not everyone needs this function, so we have disabled it by default but left the option to enable it relatively easy. You need to change the state of "BAT/BUT1" - by default the position is BUT1 so you need to separate that connection (cut between the pads) then solder the other position GPI34/BUT1 position.

This will set the voltage divider to GPI34.

To understand better the jumpers I would recommend checking the "Power Supply" section of the schematic:

https://github.com/OLIMEX/ESP32-EVB/tree/master/HARDWARE

About the code, it is not something special, there are hundreds of examples on how to use ADC pin and voltage divider to measure battery.

Notice that ESP32-EVB has no battery sense option. This is due to lack of free pins. Such option is present in our other ESP32 designs like ESP32-PoE, ESP32-PoE-ISO, among others.
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