SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
Figure 12-2086 shows an asynchronous single read operation on an address/data-multiplexed device.
For formulas to calculate timing parameters, see Section 12.3.4.5.6.1, GPMC Timing Parameters Formulas.
Table 12-4173 lists the timing bit fields to set up to configure the GPMC in asynchronous single-read mode.
When the GPMC generates a read access to an address/data-multiplexed device, it drives the address bus until nOE assertion time. For more information, see Section 12.3.4.4.7.2.3, Address/Data-Multiplexing Interface.
Address bits (A[16-1] from a GPMC perspective, A[15-0] from an external device perspective) are placed on the address/data bus, and the remaining address bits GPMC_A[22-16] are placed on the address bus. The address phase ends at nOE assertion, when the DIR signal goes from OUT to IN.
In the GPMC, when a 16-bit wide device is attached to the controller, a 32-bit word write access is split into two 16-bit word write accesses. For more information about GPMC access size and type adaptation, see Section 12.3.4.4.9.5, System Burst Versus External Device Burst Support.
Between two successive accesses, if an nCS pulse is needed: