The Versal ACAP supports a 24-bit addressing mode (QSPI24) boot mode or a 32-bit addressing (QSPI32) boot mode option. The QSPI32 boot mode option addresses flash sizes greater than 128 Mb. The QSPI boot mode supports multiple data bus widths and setups. In the QSPI boot modes, the BootROM runs at a QSPI device clock frequency between 11 MHz and 24.5 MHz dependent on the REF_CLK setting. For additional information on the quad SPI controller, see Quad SPI Controller. For details on QSPI flash support, see the Vivado Design Suite User Guide: Programming and Debugging (UG908).
The QSPI boot mode setups supported are listed in the following table.
|Quad SPI Setup||Flash Device Count||Chip Select Count||Data Width Max|
|Single (1-bit, 2-bit, 4-bit)||1||1||4|
|Dual-stacked 1 (1-bit, 2-bit, 4-bit)||2||2||4|
The boot mode image search limits are listed in Table 3.
QSPI devices support different commands. The RCU supports a common subset of commands for boot as listed in the following table.
|Boot Mode||Data Width||Read Mode||Command Code||Dummy Cycles|
|QSPI24||1||Normal read (3-Byte)||
|QSPI24||2||Dual Output fast read (3-Byte)||
|QSPI24||4||Quad Output fast read (3-Byte)||
|QSPI32||1||Normal read (4-Byte)||
|QSPI32||2||Dual Output fast read (4-Byte)||
|QSPI32||4||Quad Output fast read (4-Byte)||
|QSPI32||8||Quad Output fast read (4-Byte)||