SAM9263_14 Datasheet, PDF (179/1024 Pages) ATMEL Corporation – AT91SAM ARM-based Embedded MPU

22. Static Memory Controller (SMC)
22.1
Overview
The Static Memory Controller (SMC) generates the signals that control the access to the external memory devices or
peripheral devices. It has 8 Chip Selects and a 26-bit address bus. The 32-bit data bus can be configured to interface
with 8-, 16-, or 32-bit external devices. Separate read and write control signals allow for direct memory and peripheral
interfacing. Read and write signal waveforms are fully parameterizable.
The SMC can manage wait requests from external devices to extend the current access. The SMC is provided with an
automatic slow clock mode. In slow clock mode, it switches from user-programmed waveforms to slow-rate specific
waveforms on read and write signals. The SMC supports asynchronous burst read in page mode access for page size up
to 32 bytes.
22.2 I/O Lines Description
Table 22-1. I/O Line Description
Name
Description
NCS[7:0]
Static Memory Controller Chip Select Lines
NRD
Read Signal
NWR0/NWE
Write 0/Write Enable Signal
A0/NBS0
Address Bit 0/Byte 0 Select Signal
NWR1/NBS1
Write 1/Byte 1 Select Signal
A1/NWR2/NBS2
Address Bit 1/Write 2/Byte 2 Select Signal
NWR3/NBS3
Write 3/Byte 3 Select Signal
A[25:2]
Address Bus
D[31:0]
Data Bus
NWAIT
External Wait Signal
Type
Output
Output
Output
Output
Output
Output
Output
Output
I/O
Input
Active Level
Low
Low
Low
Low
Low
Low
Low
Low
22.3 Multiplexed Signals
Table 22-2. Static Memory Controller (SMC) Multiplexed Signals
Multiplexed Signals
Related Function
NWR0
NWE
Byte-write or byte-select access, see “Byte Write or Byte Select Access” on page 182
A0
NBS0
8-bit or 16-/32-bit data bus, see “Data Bus Width” on page 182
NWR1
NBS1
Byte-write or byte-select access see “Byte Write or Byte Select Access” on page 182
A1
NWR2
NBS2
8-/16-bit or 32-bit data bus, see “Data Bus Width” on page 182.
Byte-write or byte-select access, see “Byte Write or Byte Select Access” on page 182
NWR3
NBS3
Byte-write or byte-select access see “Byte Write or Byte Select Access” on page 182
SAM9263 [DATASHEET]
6249L–ATARM–28-Jun-13
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