Transferring Odd Bytes

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

Document ID
UG1085
Release Date
2022-09-15
Revision
2.3 English

The generic Quad-SPI controller transfers the data using the programmed data length in the immediate_data field. When the data length bytes are odd, to send the last data byte, the lower data bus is active for extra byte time than the upper data bus. For example, when the immediate_data field is 5 bytes and the stripe option is used, the bytes 0, 2, and 4 (total of 3 bytes) are sent/received on the lower data bus and 1, 3 (total 2 bytes) are sent/received on the upper data bus. The SCLK of the lower and upper are toggled accordingly.