AT91FR40161 ATMEL Corporation, AT91FR40161 Datasheet - Page 24

• 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

Byte Write or Byte Select
Access
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AT91X40 Series
Each chip select with a 16-bit data bus can operate with one of two different types of
write access:
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This option is controlled by the BAT field in the EBI_CSR (Chip Select Register) for the
corresponding chip select.
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory page.
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Figure 11 shows how to connect two 512K x 8-bit devices in parallel on NCS2.
Figure 11. Memory Connection for 2 x 8-bit Data Busses
Byte Write Access supports two byte write and a single read signal.
Byte Select Access selects upper and/or lower byte with two byte select lines, and
separate read and write signals.
The signal A0/NLB is not used.
The signal NWR1/NUB is used as NWR1 and enables upper byte writes.
The signal NWR0/NWE is used as NWR0 and enables lower byte writes.
The signal NRD/NOE is used as NRD and enables half-word and byte reads.
EBI
D8 - D15
A1 - A19
D0 - D7
NWR1
NWR0
NCS2
NRD
A0
D0 - D7
A0 - A18
Write Enable
Read Enable
Memory Enable
D8 - D15
A0 - A18
Write Enable
Read Enable
Memory Enable
1354D–ATARM–08/02