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1

The part works exactly as described in the datasheet. When A and B pins are open, and the receiver is enabled, the receiver output is high. However, since the DI and DE pins are floating, you actually don't know if the transmitter is enabled or not, and if it is enabled, you don't know what data it is sending, so there can be multiple reasons why the LED is ...


1

The general message is: set all inputs to valid logic levels A and B inputs are not connected to anything so any state can be assumed on the A and B lines and that will produce either high or low on the RO output (given that you have nRE set low i.e. you are enabling that output). If high is produced on RO then it will turn on the LED. Digging deeper this ...


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This kind of intermittent failure can be a timing problem, but it can be a power supply problem. Since the latter is easier to debug, why not start there? If you did connect all the GND/VCC pins correctly I'll designate the HT7733 regulator as a suspect, since it's pretty much the only different part between the board that work and the one that doesn't. Well,...


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Datasheet specifies an operating supply voltage between 4.5V and 5.5V. So part is not rated to work at 3.3V.


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That board you linked is an I2C level shifter. I2C buses all have pullup resistors. Often in the low kiloOhms range. I suspect the pullup resistors are simply overwhelming the sensor trying to pull down to ground. Good luck.


0

Soft UART For STM32: In this example we virtualize 6 UART full duplex in baud rate 9600. All UART work together parallelly! https://github.com/liyanboy74/soft-uart


2

You have not correctly wired the CP2102 for USB operation. Among multiple possible issues: the required connection of the VBus input is missing, which prevents the chip from placing the virtual enumeration resistor. To quote the data sheet "VBUS Sense Input. This pin should be connected to the VBUS signal of a USB network. A 5 V signal on this pin ...


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