at91sam9260-cj ATMEL Corporation, at91sam9260-cj Datasheet - Page 170

• Manufacturer Part Number: at91sam9260-cj
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 21-6.
21.7.2.3
170
AT91SAM9260
Signal Multiplexing
Connection of 2 x 8-bit Devices on a 16-bit Bus: Byte Write Option
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.
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
D[15:8]
NCS[3]
A[24:2]
NWR0
NWR1
D[7:0]
NRD
A1
A[23:1]
A[0]
Write Enable
Read Enable
Memory Enable
D[15:8]
D[7:0]
A[23:1]
A[0]
Write Enable
Read Enable
Memory Enable
6221G–ATARM–31-Jan-08
Table 21-3