34.9.2.1 Byte Write Access

Byte Write Access supports one byte write signal per byte of the data bus and a single read signal.

Note that the SMC does not allow boot in Byte Write Access mode.

  • For 16-bit devices: the SMC provides NWR0 and NWR1 write signals for respectively byte0 (lower byte) and byte1 (upper byte) of a 16-bit bus. One single read signal (NRD) is provided.

    Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory.

  • For 32-bit devices: NWR0, NWR1, NWR2 and NWR3, are the write signals of byte0 (lower byte), byte1, byte2 and byte 3 (upper byte) respectively. One single read signal (NRD) is provided.

    Byte Write Access is used to connect 4 x 8-bit devices as a 32-bit memory.

The Byte Write option is illustrated in Figure 34-6.