Operation At link time, strong symbols override weak symbols. This attribute replaces a weak symbol with a strong symbol, by choosing a particular combination of object files to link.
SCK : Serial Clock. Alternatives: SCK, SCLK, CLK, SCL
MOSI : "Master" Out → "Slave" In. Now can be read as "Main" Out "Sub" In, or can use these alternatives: SIMO, MTSR, SPID - correspond to MOSI on both main and sub devices, connects to each other SDI, DI, DIN, SI, SDA - on sub-only devices; Various abbreviations for "Serial" "Data" "In". Connects to MOSI (or alternative names) on main SDO, DO, DOUT, SO - on main-only devices; Various abbreviations for "Serial" "Data" "Out". connects to MOSI (or alternative names) on sub COPI, PICO for "peripheral and controller",[36][37] or COTI for "controller" and "target"[38]
MISO : "Master" In ← "Slave" Out. Now can be read as "Main" In "Sub" Out, or can use these alternatives: SOMI, MRST, SPIQ - correspond to MISO on both main and sub devices, connects to each other SDO, DO, DOUT, SO - on sub-only devices; connects to MISO (or alternative names) on main SDI, DI, DIN, SI - on main-only devices; connects to MISO (or alternative names) on sub CIPO, POCI,[36][37] or CITO[38]
SS : "Slave" Select (same functionality as Chip Select). Alternatives: SS, SS, SSEL, NSS, /SS, SS# (sub select) CS, CS (chip select) CE (chip enable)
