SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
GPMC access time can be dynamically controlled using an external gpmc_wait pin when the external device access time is not deterministic and cannot be defined and controlled using only the GPMC internal RDACCESSTIME, WRACCESSTIME, and PAGEBURSTACCESSTIME wait-state generator.
The GPMC features two input wait pins: gpmc_wait1, and gpmc_wait0. These pins allow control of external devices with different wait pin polarity. They also allow the overlap of wait pin assertion from different devices without affecting access to devices for which the wait pin is not asserted.
The GPMC access engine can be configured per chip-select to monitor or not the wait pin of the external memory device, based on the access type: read or write.
The GPMC access engine can be configured to monitor the wait pin of the external memory device asynchronously or synchronously with the GPMC_CLK clock, depending on the access type: synchronous or asynchronous (the GPMC_CONFIG1_i[29] READTYPE and GPMC_CONFIG1_i[27] WRITETYPE bits).