Datasheet

SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
170
external CompactFlash device is then made by accessing the address space reserved to NCS4 and/or NCS5 (i.e.,
between 0x5000 0000 and 0x5FFF FFFF for NCS4 and between 0x6000 0000 and 0x6FFF FFFF for NCS5).
All CompactFlash modes (Attribute Memory, Common Memory, I/O and True IDE) are supported but the signals
_IOIS16 (I/O and True IDE modes) and _ATA SEL (True IDE mode) are not handled.
I/O Mode, Common Memory Mode, Attribute Memory Mode and True IDE Mode
Within the NCS4 and/or NCS5 address space, the current transfer address is used to distinguish I/O mode,
common memory mode, attribute memory mode and True IDE mode.
The different modes are accessed through a specific memory mapping as illustrated on Figure 19-6. A[23:21] bits
of the transfer address are used to select the desired mode as described in Table 19-6.
Figure 19-6. CompactFlash Memory Mapping
Note: The A22 pin is used to drive the REG signal of the CompactFlash Device (except in True IDE mode).
CFCE1 and CFCE2 Signals
To cover all types of access, the SMC must be alternatively set to drive 8-bit data bus or 16-bit data bus. The odd
byte access on the D[7:0] bus is only possible when the SMC is configured to drive 8-bit memory devices on the
corresponding NCS pin (NCS4 or NCS5). The DBW field in the SMC MODE Register corresponding to the NCS4
and/or NCS5 Chip Select Register must be configured as shown in Table 19-7 to enable the required access type.
NBS1 and NBS0 are the byte selection signals from SMC and are available when the SMC is set in Byte Select
mode on the corresponding Chip Select.
The CFCE1 and CFCE2 waveforms are identical to the corresponding NCSx waveform. For details on these
waveforms and timings, refer to Section 20. “Static Memory Controller (SMC)”.
Table 19-6. CompactFlash Mode Selection
A[23:21] Mode Base Address
000 Attribute Memory
010 Common Memory
100 I/O Mode
110 True IDE Mode
111 Alternate True IDE Mode
CF Address Space
Attribute Memory Mode Space
Common Memory Mode Space
I/O Mode Space
True IDE Mode Space
True IDE Alternate Mode Space
Offset 0x00E0 0000
Offset 0x00C0 0000
Offset 0x0080 0000
Offset 0x0040 0000
Offset 0x0000 0000