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TMS320UVC5402
FIXED-POINT DIGITAL SIGNAL PROCESSOR
SPRS100A – APRIL 1999 – REVISED AUGUST 1999
14
POST OFFICE BOX 1443
HOUSTON, TEXAS 77251–1443
programmable bank-switching wait states
The programmable bank-switching logic of the ’UVC5402 is functionally equivalent to that of the ’548/’549
devices. This feature automatically inserts one cycle when accesses cross memory-bank boundaries within
program or data memory space. A bank-switching wait state can also be automatically inserted when accesses
cross the data space boundary into program space.
The bank-switching control register (BSCR) defines the bank size for bank-switching wait states. Figure 5
shows the BSCR and its bits are described in Table 4.
BNKCMP
PS-DS
Reserved
HBH
12
11
3
2
1
15
R/W-0
R-0
R/W-1
R/W-1111
BH
EXIO
0
10
R/W-0
R/W-0
LEGEND:
R = Read, W = Write
Figure 5. Bank-Switching Control Register (BSCR) [MMR Address 0029h]
Table 4. Bank-Switching Control Register (BSCR) Bit Fields
BIT
RESET
VALUE
FUNCTION
NO.
NAME
15–12
BNKCMP
1111
Bank compare. Determines the external memory-bank size. BNKCMP is used to mask the four MSBs of an
address. For example, if BNKCMP = 1111b, the four MSBs (bits 12–15) are compared, resulting in a bank size
of 4K words. Bank sizes of 4K words to 64K words are allowed.
11
PS - DS
1
Program read – data read access. Inserts an extra cycle between consecutive accesses of program read and
data read or data read and program read.
PS-DS = 0
No extra cycles are inserted by this feature.
PS-DS = 1
One extra cycle is inserted between consecutive data and program reads.
10–3
Reserved
0
These bits are reserved and are unaffected by writes.
HPI Bus holder. Controls the HPI bus holder feature. HBH is cleared to 0 at reset
.
HBH = 0
The bus holder is disabled.
HBH = 1
The bus holder is enabled. When not driven, the HPI data bus (HD[7:0]) is held in the
previous logic level.
2
HBH
0
1
BH
0
Bus holder. Controls the data bus holder feature. BH is cleared to 0 at reset.
BH = 0
The bus holder is disabled.
BH = 1
The bus holder is enabled. When not driven, the data bus (D[15:0]) is held in the previous
logic level.
External bus interface off. The EXIO bit controls the external bus-off function.
EXIO = 0
The external bus interface functions as usual.
EXIO = 1
The address bus, data bus, and control signals become inactive after completing the current
bus cycle Note that the DROM MP/MC and OVLY bits in the PMST and the HM bit of ST1
bus cycle. Note that the DROM, MP/MC, and OVLY bits in the PMST and the HM bit of ST1
cannot be modified when the interface is disabled.
0
EXIO
0
P