Does SC18IS602B MOSI go tristate/float after sending last data bit?

[JJ77]

Hi,

Most Far East Display controllers use a different 4-wire SPI bus:

MCU --> Display
============
SCLK --> SCLK
MOSI --> SDA *
MISO <-- SDA *
/CS    --> /CS
GPIO --> DCX **

*  Display Controller MOSI and MISO are tied together and this line is called SDA.
** DCX determines data to be interpreted as Data (DXC=High), or Command (DCX=Low).

For this to work, does SC18IS602B MOSI go tristate/float after sending last data bit?

Cheers,
John

[diazmarin09]

Hello John, 

I hope all is great with you. 

When the SC18IS602 MOSI output pin is not driving data on the bus, the pin signal is high.

I hope this information helps. 

Regards,

David

[JJ77]

Hi David,

Thank you for responding.

So, if MOSI turns high after the last data bit was sent, what drives MOSI high:
a. The push-pull driver high mosfet ?
b. An internal pull-up resistor/mosfet?    (if yes, what is the value?)
c. An external pull-up resistor?    (any advised values?

Hope to hear from you soon, best regards,

John

[diazmarin09]

Hello John, 

I hope all is great with you. 

In this case, all SPI signals are CMOS, so they are push-pull.

I hope this information helps. 

Regards,

David