DMA Controller

12-72

Figure 12–49. DMA Timing When Destination is an IOSTRB Bus
Cycles (H1) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Rate
Source on chip R1R2R3R4R5
DestinationIOSTRB
W1W1W1W1W2W2W2W2W3W3W3W3W4W4W4W4
1+(2+C
w)
T
Destination
IOSTRB
CwCwCwCw
1
+
(2
+
C
w
)
T
(’C30 only)
Source STRB bus R1R1R1I R2R2R2I R3R3R3I
CrCrCr(2 + Cr + 2 +
C
w) + (2 +
C
w +
max(1, Cr
C
w+1)) (
T
1)
DestinationIOSTRB bus
W1W1W1W1W2W2W2W2W3W3W3W3
max
(1
,
Cr
C
w
+
1))
(
T
1)
Destination
IOSTRB
bus
CwCwCw
Source STRB0, STRB1,
MSTRB bus R1R1R1I R2R2R2I
CrCr
(2
C
2
C
)
T
(
T
1)
Destination IOSTRB W1W1W1W1W2W2W2W2
(2
+
C
r +
2
+
C
w
)
T
+
(
T
1)
CwCw
Legend:
T = Number of transfers W = Single-cycle writes
Cr = Source-read wait states R
n
= Multicycle reads
Cw = Destination-write wait states W
n
= Multicycle writes
R = Single-cycle reads I = Internal register cycle

Write followed by read incurs in one extra cycle.