S3C2416X RISC MICROPROCESSOR
STATIC MEMORY CONTROLLER
5-11
3.6 BUS
TURNAROUND
You can configure the SMC for each memory bank to use external bus turnaround cycles between read and write
memory accesses. You can program the IDCY field for up to 15 bus turnaround wait states. This avoids bus
contention on the external memory data bus. Bus turnaround cycles are generated between external bus transfers
as follows:
read-to-read, to different memory banks
read-to-write to the same memory banks
read-to-write to different memory banks
Figure 5-12 shows a zero wait asynchronous read followed by two zero wait asynchronous writes with two
turnaround cycles added. The standard minimum of two AHB wait states are added to the read transfer, one is
added to the first write, as for any read-write transfer sequence, and three are added to the second write because
of insertion of the two turnaround cycles that are only generated after the first write transfer has been detected,
and the standard one wait state added when a write transfer is buffered.
Turnaround Cycles
A
B
C
D(A)
D(B)
D(C)
SMCLK
ADDR
nOE
nWE
nCS
DATA(IN)
DATA(OUT)
IDCY=2
Figure 5-12. Read, then two Writes (WSTRD=WSTWR=0), Two Turnaround Cycles (IDCY=2)
Summary of Contents for S3C2416
Page 122: ...BUS MATRIX EBI S3C2416X RISC MICROPROCESSOR 3 4 NOTES ...
Page 204: ...DMA CONTROLLER S3C2416X RISC MICROPROCESSOR 8 18 NOTES ...
Page 284: ...WATCHDOG TIMER S3C2416X RISC MICROPROCESSOR 11 6 NOTES ...
Page 320: ...REAL TIME CLOCK S3C2416X RISC MICROPROCESSOR 13 16 NOTES ...
Page 344: ...UART S3C2416X RISC MICROPROCESSOR 14 24 NOTES ...
Page 380: ...USB2 0 DEVICE S3C2416X RISC MICROPROCESSOR 16 34 NOTES ...
Page 432: ...2D S3C2416X RISC MICROPROCESSOR 18 38 NOTES ...
Page 446: ...HS_SPI CONTROLLER S3C2416X RISC MICROPROCESSOR 19 14 NOTES ...
Page 604: ...S3C2416X RISC MICROPROCESSOR S3C2416X RISC MICROPROCESSOR 23 22 NOTES ...
Page 638: ...PCM AUDIO INTERFACE S3C2416X RISC MICROPROCESSOR 25 18 NOTES ...
Page 670: ...ELECTRICAL DATA S3C2416X RISC MICROPROCESSOR 26 32 NOTES ...