I'm working with frdm k20D50M. I'm using the Spi, and my MOSI line has the 3.3V max level, and 2.4V low level.
I would like to work with a 0v low level. How do this? with and external translator? there are another possibility?
Is your device damaged, or is something pulling it up? Unless you have an unusually strong pull up, it should be close to zero on a logic low and no translation is necessary. Make sure also that the pin muxing has that pin configured as MOSI, not a digital input. Are you seeing serial data being sent on that line?
As David said that It is strange that the MOSI pin can not pull to LOW logic, pls check if the pin is connected to a diode, your phenomenon seems that the pin is connected to a diode or the pin is damaged.
The SPIx_OUT(MOSI) is a push-pull pin if you clear the ODE bit in corresponding PORTx_PCRn register, even if you set the pin in open drain mode, it means that the High logic can not reach if you do not enable pull-up resistor.
Hope it can help you.
Something happens with the port, I changed to another one and it works. I take the port directly from the connector in either case.
It's weird becouse the frdm is new!
thanks you both!
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