SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
Figure 12-81 and Figure 12-82 show a synchronous multiple-read operation with GPMCFCLKDivider equal to 0 and 1, respectively.
When the GPMC_CONFIG5_i[20-16] RDACCESSTIME bit field completes, control-signal timings are frozen during the multiple data transactions, corresponding to the GPMC_CONFIG5_i[27-24] PAGEBURSTACCESSTIME bit field multiplied by the number of remaining data transactions.
The nCS, nADV, nOE, and DIR signals are controlled in the same way as for a synchronous single-read operation. See Table 12-192, NOR Memory Type.
Initial latency for the first read data is controlled by RDACCESSTIME or by monitoring the WAIT signal. Successive read data are provided by the memory device every one or two GPMC_CLKOUT cycles. The PAGEBURSTACCESSTIME parameter must be set accordingly with the GPMC_CONFIG1_i[1-0] GPMCFCLKDIVIDER bit field and the memory-device internal configuration. Depending on the device page length, the GPMC checks the device page crossing during a new burst request and purposely inserts initial latency (of RDACCESSTIME) when required.
Total access time GPMC_CONFIG5_i[4-0] RDCYCLETIME corresponds to RDACCESSTIME plus the address hold time from nCS deassertion. In Figure 12-82, the programmed value of RDCYCLETIME equals RDCYCLETIME0 + RDCYCLETIME1.
After a read operation, if no other access (read or write) is pending, the data bus is driven with the previous read value. See Section 12.3.4.3.8.10, Bus Keeping Support.
Burst wraparound is enabled through the GPMC_CONFIG1_i[31] WRAPBURST bit and allows a 4-, 8-, or 16-Word16 linear burst access to wrap within its burst-length boundary through the GPMC_CONFIG1_i[24-23] ATTACHEDDEVICEPAGELENGTH bit field.