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NUC126
Aug. 08, 2018
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Rev 1.03
NUC12
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To map the whole EBI memory space, it requires 20-bit address for 8-bit data width device and 19-bit
address for 16-bit data width device. For device package that output less than 20-bit address, EBI will
map device to mirror space. For example, the external device with 18-bit EBI address on bank0, EBI
control will mapped external device to memory address 0x6000_0000 ~ 0x6003_FFFF, 0x6004_0000
~ 0x6007_FFFF, 0x6008_0000 ~ 0x600B_FFFF and 0x600C_0000 ~ 0x600F_FFFF simultaneously.
6.8.5.2
EBI Data Width Connection - Address Bus and Data Bus Multiplex Mode
The EBI controller supports device whose address bus and data bus are multiplexed. For the external
device, the connection to device needs additional latch device to latch the address. In this case,
EBI_ALE pin is connected to the latch device to latch the address value, EBI_AD pins are the input of
the latch device, and the output of the latch device is connected to the address of external device.
Figure 6.8-2 shows an example for the connection of 16-bit device with 16-bit data width. For 16-bit
device, the EBI_AD[15:0] shared by Addr[15:0] and 16-bit Data[15:0], EBI_ADR[18:16] is dedicated for
Addr[18:16] and could be connected to 16-bit device directly. The EBI_ADR[19] will be ignored in this
case. Figure 6.8-3 shows an example for the connection of 8-bit device with 8-bit data width. For 8-bit
device, only EBI_AD[7:0] shared by Addr[7:0] and 8-bit Data[7:0], EBI_AD[15:8] is dedicated for
Addr[15:8], EBI_ADR[19:16] is dedicated for Addr[19:16] and could be connected to 8-bit device
directly.
Addr[15:0]
nCS
nOE
Data[15:0]
nWE
EBI_nCSx
EBI_nRD
EBI_AD[15:0]
EBI_nWR
1M x 16-bit SRAM
Address
latch device
EBI_ALE
EBI_AD[15:0]
En
D
Q
EBI_ADR[18:16]
Addr[18:16]
nWRL
EBI_nWRL
nWRH
EBI_nWRH
External Bus Interface
Note:
x = 0 or 1
Figure 6.8-2 Connection of 16-bit Device with 16-bit EBI Data Width