SPRUJB6B November 2024 – May 2025 AM2612
The registers in this section configure the XIP-enabled OSPI peripheral, OSPI0.
MSS_OSPI_CONFIG.RTXIP_PENDING is a 3-bit field in the MSS_OSPI_CONFIG register that indicates the real-time XIP status to 8051 FOTA firmware for arbitration if the peripheral needs to differentiate between real-time XIP and non-real time XIP requests. When the real-time XIP is pending, the register is programmed with 3'b111. When the real-time XIP is done, the register is programmed with 3'b000. Configuration changes must be done when the FSS (Flash Subsystem) is idle, not configured, or when there are no active transactions.
MSS_OSPI_CONFIG.CONFIG_ICLK_SEL is a 3-bit field in the MSS_OSPI_CONFIG register that is a mux select to use either the internal loopback clock OSPI0_CLKLB as the OSPI0 input clock, or to use the DQS signal OSPI_DQS as the OSPI0 input clock. The selected clock is the adapted loopback device clock used by the read delay capture circuit to sample the read data as it returns to the MCU from the flash memory device. Write 3'b111 to select the loopback clock OSPI0_CLKLB as the OSPI0 input IO clock. Write 3'b000 to select the OSPI0_DQS as the OSPI0 input IO clock. Configuration changes must be done when the FSS is idle, not configured, or when there are no active transactions.
The register OSPI_BOOT_CONFIG_MASK holds the OSPI image boot size. The register OSPI_BOOT_CONFIG_SEG is the OSPI segment seelctor for programmed boot size. The BOOT_CONFIG_SEG will replace the upper 20 bits of the internal address based on segment size derived from BOOT_MASK, which will determine the bits to be replaced.
The register FSS_OE_NEXT_EN is used to enable/disable the early OE_N signal for the OSPI0 IO pads. Setting these bits to 3'b111 enabled the early OE_N signal, which comes out one clock cycle early for the OSPI0 IO pads, which triggers the OSPI0 IO pads to switch to input mode one clock cycle earlier. This is used in high-frequency flash read use cases to account for pad delays and data byte loss in the peripheral FIFO. Write 3'b000 to disable the early OE_N signal.