Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

why 3-wire spi have 4-prot ??

Dear ALL I want to use the spi in sopc builder . but I find it have 4 paort . i can connect it to my extern device . I want to know how to do it . thanks!
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

You should get four signals at the top level:

sclk (serial clock)

mosi (master out slave in) --> so if you use a SPI master in SOPC Builder this is your serial output

miso (master in slave out) --> so if you use a SPI master in SOPC Builder this is your serial input

ss/ss_n (slave select)

So if the component you are trying to talk to can only do reads for example you don't need to use the mosi signal (your component can't do anything with the data).