SPI/QSPI Flash memories provide a storage solution for systems with limited space, pins, and power.
The ROM code support for SPI/QSPI devices has the following characteristics:
- 24-bit addressing, up to 128 Mbit (16 MiB), no banking
- QSPI1 on CS0 is the communication interface
- Uses Mode 3:
- Clock inactive state = high
- Data input captured on rising edge of clock
- Data output generated on falling edge of clock
- QSPI 4-bit data read mode at 48 MHz in configuration port mode
- Read command is 0x6B (Fast Quad Read), 3 address bytes,1 dummy bytes and read type is quad read
- ROM will not perform any quad-enable sequence nor bank register update
- SPI 1-bit data read mode at 12 MHz in configuration port mode
- Read command is 0x03 (Single Read), 3 address bytes, 0 dummy bytes and read type is normal read.
- Up to four redundant images can be stored on SPI/QSPI flash. The offset between them is set in sysboot[7:6] as described in Table 32-8. If not using the redundant SBL feature, the offset set in sysboot[7:6] is a don't care. A booting image is considered to be present , when the first 4 bytes word is not equal to 0000 0000h or FFFF FFFFh.
Note: ROM code does not perform any specific action to detect, reset or power up the QSPI device. QSPI is assumed to be properly powered and reset to be completed before every attempt to boot by ROM code.