Hello everyone. I've prepared a circuit which is meant to translate logic levels within an SPI interface. Unfortunately, my circuit doesn't work. The whole project is a development board for Orange Pi platform and I want to use this SPI interface for programming flash memories. Additionaly, the platform has to handle both 1.8V- and 3.3V-supplied chips. Here is my design:
OC_OUT3 is an open-collector pin which allows to enable the circuit using the low state (that's a requirement) VOUT is voltage which is selected by a relay (1.8V or 3.3V). As far as I read, VCCy must be less or equal the VCCa. That's why my Master device has been attached to the Y-signed pins and slave to the opposite ones. I can't make a connection. I have checked it up for 2 types of memory. MX25U6435F (1.8V) and Winbound W25Q64FW. Vccy (I don't know why in my schematic is VCCb) is connected for good.
Could you give me some tips where should I look for a possible causes?
Kindly check again the ADG3304 datasheet on page 17. It was mentioned that:
For proper operation of the ADG3304, the voltage applied to the VCCA must be less than or equal to the voltage applied to VCCY.
I think you got the opposite?