Datasheet

SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
140
19.6.5.3 Read/Write Signals
In I/O mode and True IDE mode, the CompactFlash logic drives the read and write command signals of the SMC
on CFIOR and CFIOW signals, while the CFOE and CFWE signals are deactivated. Likewise, in common memory
mode and attribute memory mode, the SMC signals are driven on the CFOE and CFWE signals, while the CFIOR
and CFIOW are deactivated. Figure 19-4 demonstrates a schematic representation of this logic.
Attribute memory mode, common memory mode and I/O mode are supported by setting the address setup and
hold time on the NCS4 (and/or NCS5) chip select to the appropriate values.
Figure 19-4. CompactFlash Read/Write Control Signals
Table 19-6. CFCE1 and CFCE2 Truth Table
Mode CFCE2 CFCE1 DBW Comment SMC Access Mode
Attribute Memory NBS1 NBS0 16 bits Access to Even Byte on D[7:0] Byte Select
Common Memory
NBS1 NBS0 16bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
Byte Select
1 0 8 bits Access to Odd Byte on D[7:0] Don’t Care
I/O Mode
NBS1 NBS0 16 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
Byte Select
1 0 8 bits Access to Odd Byte on D[7:0] Don’t Care
True IDE Mode
Task File 1 0 8 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[7:0]
Don’t Care
Data Register 1 0 16 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
Byte Select
Alternate True IDE Mode
Control Register
Alternate Status Read
0 1 Don’t Care Access to Even Byte on D[7:0] Don’t Care
Drive Address 0 1 8 bits Access to Odd Byte on D[7:0] Don’t Care
True IDE Standby Mode or Address
Space is not assigned to CF
1 1 Don’t Care Don’t Care Don’t Care
SMC
NRD
NWR0_NWE
A21
CFIOR
CFIOW
CFOE
CFWE
1
1
CompactFlash Logic
External Bus Interface
1
1
1
0
A20
1
0
1
0
1
0