Datasheet

SAM9G20
DS60001516A-page 154  2017 Microchip Technology Inc.
Figure 20-6: Connection of 2 x 8-bit Devices on a 16-bit Bus: Byte Write Option
20.7.2.3 Signal Multiplexing
Depending on the BAT, only the write signals or the byte select signals are used. To save IOs at the external bus interface, control signals
at the SMC interface are multiplexed. Table 20-3 shows signal multiplexing depending on the data bus width and the byte access type.
For 32-bit devices, bits A0 and A1 are unused. For 16-bit devices, bit A0 of address is unused. When Byte Select Option is selected, NWR1
to NWR3 are unused. When Byte Write option is selected, NBS0 to NBS3 are unused.
SMC
A1
NWR0
NRD
NCS[3]
Write Enable
Read Enable
Memory Enable
NWR1
Write Enable
Read Enable
Memory Enable
D[7:0] D[7:0]
D[15:8]
D[15:8]
A[24:2]
A[23:1]
A[23:1]
A[0]
A[0]