Boot-Up Using The Hi08 Host Port; Hi08 Read And Write Operations In Big Endian Mode; Hi08 Boot Modes - Motorola DSP56303 User Manual

Boot-up Using the HI08 Host Port

A similar operation occurs when the HI08 is initialized in Big Endian mode by clearing the
Host Little Endian bit (ICR[5]=HLEND). Big Endian mode is depicted in Figure 6-5.
HTX/HRX Register: 23
DSP side
Host side
Host 32-bit
internal register
Figure 6-5. HI08 Read and Write Operations in Big Endian Mode
6.5 Boot-up Using the HI08 Host Port
The DSP56300 core has eight bootstrap operating modes to start up after reset. As the
processor exits the Reset state the value at the external mode pins
/ and
MODC IRQC MODD
and MD) of the Operating Mode Register (OMR). These bits determine the bootstrap
operating mode. Modes C, D, E and F use the HI08 host port to bootstrap the application code
to the DSP. Table 6-7 describes these modes.
Mode MODD
C 1
D 1
E 1
F 1
The bootstrap program is factory-programmed into an internal 192-word by 24-bit bootstrap
ROM at locations $FF0000–$FF00BF of P memory. This program can load program RAM
segment from the HI08 host port. When any of the modes in the preceding table are used, the
core begins executing the bootstrap program and configures the HI08 based on the OMR
mode bits.
6-12
High Byte
Host bus address:
xx
/ are loaded into the Chip Operating Mode bits (MA, MB, MC
IRQD
Table 6-7. HI08 Boot Modes
MODC MODB MODA
1 0
1 0
1 1
1 1
DSP56303 User's Manual
aa bb
bb
aa
$5 $6
aa bb
HI08 Bootstrap Description
0 ISA/DSP5630x mode
1 HC11 non-multiplexed bus mode
0 8051 multiplexed bus mode
1 MC68302 bus mode
0
cc
Low Byte
cc
(read/write last!)
$7
cc
/
MODA IRQA, MODB
/ ,
IRQB