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Can a SDI pin be connected to a SDO pin?
Anyway, SPI data pins are not bi-directional buffers, so SDI pin on one chip should always be connected to SDO (or MOSI) pin on the other chip. The statement you’ve quoted from WP is totally wrong. SDI on a chip be connected to SDO on the other chip, regardless of whichever is assumed to be master or slave.
Why are there no pull up resistors in SPI?
In general, there is no need for pull up resistors in a SPI implementation, because the pins use a push-pull configuration, rather than Open Drain. The output pins are capable of actively creating their own logical high and low states, rather than relying on pull up resistors to generate a default state.
What are the three primary pins in SPI?
Typically, the three primary pins of the SPI system, SCK, MISO and MOSI, will be connected in a bus fashion, each tapping into the line at some point along the way. In rare instances though, chips can be daisy chained together with the MISO pin of one chip connected to the MOSI pin of the next chip in order, with SCK and CS connected bus fashion.
What are the three signaling lines in SPI?
Every SPI implementation will include three signaling lines at a minimum: the clock line called SCK, the Master In / Slave Out line called MISO (Me-So) and the Master Out / Slave In line called MOSI (Moh-See).
Is there ambiguity between SDI and SDO names?
If you name the nets SDI and SDO then there is an ambiguity at either the master or the slave as one or the other must cross connect relative to the pin names, combine with a (ex)contractor who was rather lacking in attention to detail and nets mostly buried inside a 6 layer board… Oh how we laughed.
The MOSI/MISO convention requires that, on devices using the alternate names, SDI on the master be connected to SDI on the slave. Which confused me a bit. In the diagram, SDI is wired with SDO and naming is relative to the device the pin is in, which contradicts wikipedia (SDI naming is always relative to the master).
Is the SDI name relative to the Master?
In the diagram, SDI is wired with SDO and naming is relative to the device the pin is in, which contradicts wikipedia (SDI naming is always relative to the master). So, in essence, is the Wikipedia article wrong?