RM0082
DDR memory controller (MPMC)
Doc ID 018672 Rev 1
117/844
Early burst termination
Unlike the AHB bus protocol, the Memory Controller core bus protocol does not allow for
early burst termination. As a result, the Memory Controller core requires the master to
complete the whole READ/WRITE transaction of the length specified to the Memory
Table 58.
AHB-Memory controller translation example
AHBx transaction
Memory controller transaction
Address
Burst size
AHBx
HBURST
Bytes per beat
(AHBx HSIZE)
Address
Length
AHBx
Address
SINGLE
Byte, half-word or
word
AHBx Address
1 x (AHBx HSIZE)
AHBx
Address
INCR4
Byte, half-word or
word
AHBx Address
2 x (AHBx HSIZE)
AHBx
Address
INCR8
Byte, half-word or
word
AHBx Address
8 x (AHBx HSIZE)
AHBx
Address
INCR16
Byte, half-word or
word
AHBx Address
16 x (AHBx HSIZE)
AHBx
Address
WRAP4
(offset n= 0-3)
Byte, half-word or
word
Transaction#1:
AHBx Address
Transaction #2:
Wrapped AHBx Address
Transaction #1:
(4 - n) x (AHBx
HSIZE)
Transaction #2:
n x (AHBx HSIZE)
AHBx
Address
WRAP8
(offset n= 0-7)
Byte, half-word or
word
Transaction#1:
AHBx Address
Transaction #2:
Wrapped AHBx Address
Transaction #1:
(8 - n) x (AHBx
HSIZE)
Transaction #2:
n x (AHBx HSIZE)
AHBx
Address
WRAP16
(offset n= 0-
15)
Byte, half-word or
word
Transaction#1:
AHBx Address
Transaction #2:
Wrapped AHBx Address
Transaction #1:
(16 - n) x (AHBx
HSIZE)
Transaction #2:
n x (AHBx HSIZE)
AHBx
Address
INCR
(for each
beat)
Byte or half-word
AHBx Address
1 x (AHBx HSIZE)
AHBx
Address
INCR
Word
Transaction 1:
AHBx HADDR
Transaction 2:
AHBx HADDR+blk size
Transaction 3:
2 x (AHBx HADDR+blk
size)
(1)
1.
blk size is the value in ahbX_rdnct or abhX_wrcnt.
(AHBx read_cnt)
or
(AHBx write_cnt)
(2)
2.
Programmable value