Motorola TMS320C6711D - Manual (Page 60)

TMS320C6711D
FLOATINGĆPOINT DIGITAL SIGNAL PROCESSOR
SPRS292A − OCTOBER 2005 − REVISED NOVEMBER 2005
60 POST OFFICE BOX 1443
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HOUSTON, TEXAS 77251−1443
EMIF big endian mode correctness
The HD8 pin device endian mode (LENDIAN) selects the endian mode of operation (Little or Big Endian). For
the device, Little Endian is the default setting.
The HD12 pin (EMIF Big Endian Mode Correctness) [EMIFBE] enhancement allows the flexibility to change the
EMIF data placement on the EMIF bus.
When using the default setting of HD12 = 1, the EMIF will present 8-bit and 16-bit data on the ED[7:0] side of
the bus if using Little Endian mode (HD8 = 1) and to the ED[31:24] side of the bus if using Big Endian mode.
Figure 14 shows the mapping of 16-bit and 8-bit devices with EMIF endianness correction.
EMIF DATA LINES (PINS) WHERE DATA PRESENT
ED[31:24] (BE3) ED[23:16] (BE2) ED[15:8] (BE1) ED[7:0] (BE0)
32-Bit Device in Any Endianness Mode
16-Bit Device in Big Endianness Mode 16-Bit Device in Little Endianness Mode
8-Bit Device in Big
Endianness Mode
8-Bit Device in Little Endianness Mode
Figure 14. 16/8-Bit EMIF Big Endian Mode Correctness Mapping (HD12 = 1)
When HD12 = 0, enabling EMIF endianness correction, the EMIF will present 8-bit and 16-bit data on the ED[7:0]
side of the bus, regardless of the endianess mode (see Figure 15).
EMIF DATA LINES (PINS) WHERE DATA PRESENT
ED[31:24] (BE3) ED[23:16] (BE2) ED[15:8] (BE1) ED[7:0] (BE0)
32-Bit Device in Any Endianness Mode
16-Bit Device in Any Endianness Mode
8-Bit Device in Any Endianness Mode
Figure 15. 16/8-Bit EMIF Big Endian Mode Correctness Mapping (HD12 = 0)
This new endianness correction functionality does not affect systems using the default value of HD12=1.
This new feature does not affect systems operating in Little Endian mode.