EMIF Registers
9-14
The read hold and write hold fields have been increased by one bit, to allow
greater asynchronous configuration possibilities. The MTYPE field has been
increased by one bit to allow for 8-, 16-, and 32-bit interface options for all
memory types.
The ’C6211/C6711 EMIF supports memory widths of 8-, 16-, and 32-bits, in-
cluding reads and writes of both big and little endian devices. There is no dis-
tinction between ROM and asynchronous interface.
For all memory types, the address is internally shifted to compensate for
memory widths of less than 32 bits. The least-significant address bit is always
output on external address pin EA[2], regardless of the width of the device. Ac-
cesses to 8-bit memories have logical address bit 0 output on EA[2].
Packing and unpacking is automatically performed by the EMIF for word ac-
cesses to external memories of less than 32 bits. For a 32-bit write to an 8-bit
memory, the data is automatically unpacked into bytes such that the bytes are
written to byte address N, N+1, N+2, then N+3. Likewise for 32-bit reads from
a 16-bit memory, data is taken from halfword address N then N+1, packed into
a 32-bit word, then written to its destination. The byte lane used depends on
the endianness of the system as shown in Figure 9–9.
Figure 9–9. TMS320C6211/C6711 Byte Alignment by Endianness
little endian
device
8-bit
little endian
16-bit device
big endian
device
8-bit
big endian
16-bit device
32-bit device
ED[7:0]
ED[15:8]
ED[23:16]
ED[31:24]
TMS320C6211/C6711