Atmel AT32UC3A3128, Manual

Page: 169 / 1021

169
32072H–AVR32–10/2012
AT32UC3A3
14.6.5 CompactFlash Support
The External Bus Interface integrates circuitry that interfaces to CompactFlash devices.
The CompactFlash logic is driven by the SMC on the NCS[4] and/or NCS[5] address space.
Writing to the HMATRIX.SFR6.CS4A and/or HMATRIX.SFR6.CS5A bits the appropriate value
enables this logic.
Access to an external CompactFlash device is then made by accessing the
address space reserved to NCS[4] and/or NCS[5].
Attribute Memory, Common Memory, I/O modes are supported but the signals _IOWR, _IOIS16
(I/O mode) are not handled.
14.6.5.1 I/O Mode, Common Memory Mode, Attribute Memory Mode
Within the NCS[4] and/or NCS[5] address space, the current transfer address is used to distin-
guish I/O mode, common memory mode andattribute memory mode.
The different modes are accessed through a specific memory mapping as illustrated on Figure
14-2 on page 169 . ADDR[23:21] bits of the transfer address are used to select the desired mode
as described in Table 14-4 on page 169 .
Figure 14-2. CompactFlash Memory Mapping
Note: The ADDR[22] I/O line is used to drive the REG signal of the CompactFlash Device.
14.6.5.2 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 DATA[7:0] bus is only possible when the SMC is config-
Table 14-4. CompactFlash Mode Selection
ADDR[23:21] Mode Base Address
000 Attribute Memory
001 I/O Mode (Write operations)
010 Common Memory
100 I/O Mode (Read operations)
I/O Mode Space
(Read operations)
Common Memory Mode Space
Attribute Memory Mode Space
Offset 0x0080 0000
Offset 0x0040 0000
Offset 0x0000 0000
CF Address Space
I/O Mode Space
(Write operations)
Offset 0x0020 0000