AT91FR40161 ATMEL Corporation, AT91FR40161 Datasheet - Page 21

• Manufacturer Part Number: AT91FR40161
• Description: The AT91FR40161 Features 136 K Bytes of On-chip SRAM, 2M Bytes of Flash, an External Bus Interface, a 3-channel Timer/Counter, 2 ...
• Manufacturer: ATMEL Corporation

Chip Select Lines
1354D–ATARM–08/02
The EBI provides up to eight chip select lines:
•
•
By exchanging address lines for chip select lines, the user can optimize the EBI to suit
the external memory requirements: more external devices or larger address range for
each device.
The selection is controlled by the ALE field in EBI_MCR (Memory Control Register). The
following combinations are possible:
Figure 7. Memory Connections for Four External Devices
Note:
EBI
Chip select lines NCS0 - NCS3 are dedicated to the EBI (not multiplexed).
Chip select lines CS4 - CS7 are multiplexed with the top four address lines A23 -
A20.
A20, A21, A22, A23 (configuration by default)
A20, A21, A22, CS4
A20, A21, CS5, CS4
A20, CS6, CS5, CS4
CS7, CS6, CS5, CS4
NCS0 - NCS3
For four external devices, the maximum address space per device is 16M bytes.
D0 - D15
A0 - A23
NWRx
NRD
8 or 16
NCS0
NCS1
AT91X40 Series
NCS2
D0 - D15 or D0 - D7
NCS3
Memory Enable
Output Enable
Write Enable
A0 - A23
Memory Enable
Memory Enable
Memory Enable
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