Host Base Address Register (Hbar) - Motorola DSP56367 User Manual

Host Interface (HDI08)
HDI08 – DSP-Side Programmer's Model
8.5.5

HOST BASE ADDRESS REGISTER (HBAR)

The HBAR is used in multiplexed bus modes. This register selects the base address where the
host side registers are mapped into the bus address space. The address from the host bus is
compared with the base address as programmed in the base address register. If the addresses
match, an internal chip select is generated. The use of this register by the chip select logic is
shown in Figure 8-5.
Figure 8-4 Host Base Address Register (HBAR) (X:$FFFFC5)
15 14 13 12
- Reserved bit. Read as 0. Should be written with 0, for future compatibility.
8.5.5.1 HBAR Base Address (BA[10:3]) Bits 0-7
These bits define the base address where the host side registers are mapped into the bus
address space.
8.5.5.2 HBAR Reserved Bits 8-15
These bits are reserved. They read as zero and should be written with zero for future
compatibility.
HAD[0-7]
HAS
HA[8:10]
DSP Peripheral
data bus
8-12
11 10 9 8
Latch
A[3:7]
Base
Address 8 bits
register
BA[3:7]
Figure 8-5 Self Chip Select logic
DSP56367
7 6 5 4
BA10 BA9 BA8 BA7
Chip select
3 2 1 0
BA6 BA5 BA4 BA3
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