Texas Instruments TMS320C3x - Manual (Page 378)

TMS320C32 Boot Loader
11-23 Using the TMS320C31 and TMS320C32 Boot Loaders
11.2.5 Boot-Loader Hardware Interface
The hardware interface for the memory boot load uses the STRBX_B3 through
STRBX_B0 pins as strobe byte-enable pins (see Figure 11–8). The hardware
interface is independent of the boot source memory width. This interface
is identical to the 32-bit-wide memory interface described in Case 2, in Section
10.6 on page 10-20. For 16-bit memory widths, remove the two left-most
memory devices of Figure 11–8. For 8-bit memory widths, remove all but the
right-most of the memory devices of Figure 11–8.
Figure 11–8. External Memory Interface for Source Data Stream Memory Boot Load
’C32
STRBX_B3
STRBX_B2
STRBX_B1
STRBX_B0
D(31–24)
D(23–16)
D(15–8)
D(7–0)
I/O(7- 0)
A
23
A
22
A
21
A
20
A
2
A
1
A
0
. . . . . .
A
23
A
22
A
21
A
20
A
2
A
1
A
0
. . .
CS
I/O(7- 0)
. . .
A
23
A
22
A
21
A
20
A
2
A
1
A
0
. . .
CS
I/O(7- 0)
. . .
A
23
A
22
A
21
A
20
A
2
A
1
A
0
. . .
CS
I/O(7- 0)
. . .
A
23
A
22
A
21
A
20
A
2
A
1
A
0
. . .
CS
16–bit wide EPROM 32–bit wide EPROM
8–bit wide EPROM
11.2.6 TMS320C32 Boot-Loader Precautions
The interrupt flags are not reset by the boot-loader function. If pending interrupts
are to be avoided when interrupts are enabled, clear the IF register before enabling
interrupts.
The MCBL/MP pin should remain high during the entire boot-loading execution,
but it can be changed subsequently at any time. The ’C32 does not need to be
reset after the MCBL/MP pin is changed. During the change, the ’C32 should
not access addresses Oh–FFh. The memory space Oh–FFFh is mapped to
external memory three clock cycles after changing the MCBL/MP pin.