HOST INTERFACE (HI)
MOTOROLA
PORT B
5 - 63
5.3.6.4
Example Circuits
Figure 5-41, Figure 5-42, and Figure 5-43 illustrate the simplicity of the HI. The
MC68HC11 in Figure 5-42 has a multiplexed address and data bus which requires that
the address be latched. Although the HACK is not used in this circuit, it is pulled up. All
unused input pins should be terminated to prevent erroneous signals. When determining
whether a pin is an input, keep in mind that it may change during reset or while changing
Port B between general purpose I/O and HI functions.
The MC68000 (see Figure 5-42) can use a MOVEP instruction with word and long-word
data size to transfer multiple bytes. If an MC68020 or MC68030 is used, dynamic bus siz-
ing can be used to transfer multiple bytes with any instruction.
Figure 5-43 is a high level block diagram of a system using a single host to control multiple
DSPs. In addition, the DSPs use the SSI to network together the DSPs and multiple
codecs. This system, as shown with four DSPs, can process 80 million instructions per
A0 - A2
+5 V
DSP56002
MC68HC11
IRQ
A8 - A15
E
R/W
AS
A0/D0 - A7/D7
HACK
(HOST ACKNOWLEDGE)
HREQ
(HOST REQUEST)
HEN
(HOST ENABLE)
HR/W
(HOST READ/WRITE)
HA0 - HA2
(HOST ADDRESS)
H0 - H7
(HOST DATA)
ADDRESS
DECODE
LE
ADDRESS
LATCH
+5 V
A3 - A7
Use LDA and STA for 8-Bit Transfers.
Use LDD and STD for 16-Bit Transfers.
Figure 5-41 MC68HC11 to DSP56002 Host Interface
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..
Содержание DSP56002
Страница 380: ......
Страница 382: ......
Страница 390: ...Freescale Semiconductor I Freescale Semiconductor Inc For More Information On This Product Go to www freescale com nc...