SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
In asynchronous read mode, for single and paged accesses, the GPMC_CONFIG5_i[20-16] RDACCESSTIME bit field (where i = 0 to 3) defines the number of GPMC_FCLK cycles from start access time to the GPMC_FCLK rising edge used for the first data capture. RDACCESSTIME must be programmed to the rounded greater value (in GPMC_FCLK cycles) of the read access time of the attached memory device.
In synchronous read mode, for single or burst accesses, RDACCESSTIME defines the number of GPMC_FCLK cycles from the start access time to the GPMC_FCLK rising edge corresponding to the GPMC output clock rising edge used for the first data capture.
GPMC output clock, which is sent to the memory device for synchronization with the GPMC controller, is internally retimed to correctly latch the returned data. The GPMC_CONFIG5_i[4-0] RDCYCLETIME bit field must be greater than RDACCESSTIME to let the GPMC latch the last return data using the internally retimed GPMC output clock.
The external WAIT signal can be used in conjunction with RDACCESSTIME to control the effective GPMC data-capture GPMC_FCLK edge on read access in asynchronous and synchronous modes. For more information about wait monitoring, see Section 12.3.4.3.7.3.1, WAIT Pin Monitoring Control.