SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
Data is shifted one bit at a time from the DR pin to the RSRs or from the XSRs to the DX pin. The time for each bit transfer is controlled by the rising or falling edge of a clock signal.
The receive clock signal (CLKR) controls bit transfers from the DR pin to the RSRs. The transmit clock signal (CLKX) controls bit transfers from the XSRs to the DX pin. CLKR or CLKX can be derived from a pin at the boundary of the McBSP or derived from inside the McBSP. The polarities of CLKR and CLKX are programmable.
Figure 20-7 shows how the clock signal controls the timing of each bit transfer on the pin.