SN32F280 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 217
Version 1.1
- NOIDLE = 0:
A[N:0]
ADDR0
RDSETUP
(0, 1, 2, …)
RDSTRB
(1, 2, 3, …)
AD[15:0]
CSn
OE
RDHOLD
(0, 1, 2, …)
IDLE
RDSETUP
(0, 1, 2, …)
RDSTRB
(1, 2, 3, …)
RDHOLD
(0, 1, 2, …)
IDLE
ADDR1
DATA0
DATA1
- NOIDLE = 1:
A[N:0]
ADDR0
RDSETUP
(0, 1, 2, …)
RDSTRB
(1, 2, 3, …)
AD[15:0]
CSn
OE
RDHOLD
(0, 1, 2, …)
RDSETUP
(0, 1, 2, …)
RDSTRB
(1, 2, 3, …)
RDHOLD
(0, 1, 2, …)
IDLE
ADDR1
DATA0
DATA1
18.5.6 AHB Transaction Width Conversion
The mapping of AHB transactions to an external device depends on the data width of the external device and whether
the byte lanes of the external device are supported or not. The EBI will automatically translate the different AHB
transaction width to external device transactions which matches the external bus capabilities of the device.
If the AHB master (CPU) transaction width is larger than the external bus transaction width. The EBI will split and
translate the AHB transaction into consecutive multiple external transactions which have consecutively
incrementing the address and start with the least significant data from AHB transaction.
If the AHB master (CPU) transaction width is smaller than the external bus transaction width. The EBI behaviour
depends on whether the byte lanes are available or not. Reads either use byte lanes to select the required data
when it is available, or read according to the full data bus width of the external device and ignore the superfluous
data when a byte lane is not available. Writes either use a byte lane to select the required data when it is available,