SPNS254A June 2022 – March 2024 TMS570LC4357-SEP
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
Wait states are cycles the CPU must wait in order to retrieve data from the memories which have access times longer than a CPU clock. Memory wrapper, SCR interconnect and the CPU itself may introduce additional cycles of latency due to logic pipelining and synchronization. Therefore, the total latency cycles as seen by the CPU can be more than the number of wait states to cover the memory access time.
Figure 6-2 shows only the number of programmable wait states needed for L2 flash memory at different frequencies. The number of wait states is correlated to HCLK frequency. The clock ratio between CPU clock (GCLKx) and HCLK can vary. Therefore, the total number of wait states in terms of GCLKx can be obtained by taking the programmed wait states multiplied by the clock ratio.
There is no user programmable wait state for L2 SRAM access. L2 SRAM is clocked by HCLK and is limited to maximum 150 MHz.
L2 flash is clocked by HCLK and is limited to maximum 150 MHz. The L2 flash can support zero data wait state up to 45 MHz.