We have two Intel Joule development kits, one containing the 550x module and the other containing the 570x one.
The problem we are facing is that the voltage level of the signals on the J12 and J13 connectors are only going up to 1.8V instead of 3.3V as specified in the datasheet.
On J13 for example I can successfully measure 5V on pins 2 and 4, 3.3V on pins 6 and 8, and 1.8V on pins 10 and 12 but when I try to output a signal on the SPI port, it only goes up to 1.8V instead of 3.3V.
This is happening to on both development boards.
I does anyone have the same problem, is there a issue with the level sifters?
Any help is appreciated,
Thank you for your interest in the Intel® Joule™ Products.
The reason behind the 1.8 V is that ISH_GPIO signals require pull-up resistors on the 3.3V side of the level shifter to achieve the target level.
This is required due to the open-drain nature of the level-shifter design. Information regarding pull-up resistors can be found in the Joule Expansion Board Hardware Guide, in section 10:
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