SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
During synchronous accesses with WAIT pin monitoring enabled, the WAIT pin is captured synchronously with GPMC output clock, using the rising edge of this clock.
The WAIT signal can be programmed to apply to the same clock cycle in which it is captured. Alternatively, it can be sampled one or two GPMC output clock cycles ahead of the clock cycle to which it applies. This pipelining is applicable to the entire burst access and to all data phases in the burst access. This wait pipelining depth is programmed in the GPMC_CONFIG1_i[19-18] WAITMONITORINGTIME bit field (where i = 0 to 3), and is expressed as a number of GPMC output clock cycles.
In synchronous mode, when WAIT pin monitoring is enabled (the GPMC_CONFIG1_i[22] WAITREADMONITORING bit), the effective access time is a logical AND combination of the RDACCESSTIME timing completion and the wait-deasserted state detection.
Depending on the programmed value of WAITMONITORINGTIME, the WAIT pin must be at a valid level, either asserted or deasserted:
Similarly, during a multiple-access cycle (burst mode), the effective access time is a logical AND combination of PAGEBURSTACCESSTIME timing completion and the WAIT-INACTIVE state. The wait pipelining-depth programming applies to the whole burst access.
Figure 12-2082 shows wait behavior during a synchronous read burst access.
The WAIT signal is active low. WAITMONITORINGTIME = 0b00, 0b01.