AT32UC3A0512_1 Datasheet, PDF (373/826 Pages) ATMEL Corporation – AVR32 32-Bit Microcontroller

AT32UC3A
Figure 27-8. Connection of 2x16-bit Data Bus on a 32-bit Data Bus (Byte Select Option)
D[15:0]
D[31:16]
A[25:2]
NWE
NBS0
NBS1
SMC
NBS2
NBS3
NRD
NCS[3]
D[15:0]
A[23:0]
Write Enable
Low Byte Enable
High Byte Enable
Read Enable
Memory Enable
D[31:16]
A[23:0]
Write Enable
Low Byte Enable
High Byte Enable
Read Enable
Memory Enable
Table 27-2. SMC Multiplexed Signal Translation
Signal Name
32-bit Bus
Device Type
1x32-bit
2x16-bit
Byte Access Type (BAT) Byte Select
Byte Select
NBS0_A0
NBS0
NBS0
NWE_NWR0
NWE
NWE
NBS1_NWR1
NBS1
NBS1
NBS2_NWR2_A1
NBS2
NBS2
NBS3_NWR3
NBS3
NBS3
4 x 8-bit
Byte Write
NWR0
NWR1
NWR2
NWR3
16-bit Bus
1x16-bit
2 x 8-bit
Byte Select
Byte Write
NBS0
NWE
NWR0
NBS1
NWR1
A1
A1
8-bit Bus
1 x 8-bit
A0
NWE
A1
27.6.4
Standard Read and Write Protocols
In the following sections, the byte access type is not considered. Byte select lines (NBS0 to
NBS3) always have the same timing as the A address bus. NWE represents either the NWE sig-
nal in byte select access type or one of the byte write lines (NWR0 to NWR3) in byte write
access type. NWR0 to NWR3 have the same timings and protocol as NWE. In the same way,
NCS represents one of the NCS[0..3] chip select lines.
32058H–AVR32–03/09
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