Datasheet

SAM9G20
DS60001516A-page 168  2017 Microchip Technology Inc.
Figure 20-22: TDF Optimization: No TDF wait states are inserted if the TDF period is over when the next
access begins
20.10.3 TDF Optimization Disabled (TDF_MODE = 0)
When optimization is disabled, tdf wait states are inserted at the end of the read transfer, so that the data float period is ended when the
second access begins. If the hold period of the read1 controlling signal overlaps the data float period, no additional tdf wait states will be
inserted.
Figure 20-23, Figure 20-24 and Figure 20-25 illustrate the cases:
• read access followed by a read access on another chip select,
• read access followed by a write access on another chip select,
• read access followed by a write access on the same chip select,
with no TDF optimization.
A
[25:2]
NCS0
MCK
NRD
NWE
D[31:0]
Read to Write
Wait State
TDF_CYCLES = 6
read access on NCS0 (NRD controlled)
NRD_HOLD= 4
NWE_SETUP= 3
write access on NCS0 (NWE controlled)