Motorola DSP56012 - Manual (Page 143)

Parallel Host Interface
Host Interface (HI)
MOTOROLA DSP56012 User’s Manual 4-63
Figure 4-37
Host to DSP DMA Procedure
WRITE ICR
HOST PR
OCESSOR
X:$FFE8
HOST CONTR
OL
REGISTER (HCR)
P:$007E
A
V
AILABLE FOR HOST COMMAND
F
AST INTERR
UPT
OR
LONG INTERR
UPT
P:$0000
HOST TRANSMIT
D
A
T
A
VECT
OR
P:$0032
1.
PR
OGRAM DMA CONTR
OLLER.
—ST
AR
T ADDRESS
—BYTE COUNT —TRANSFER DIRECTION —ST
AR
T DMA CHANNEL
TXH TXM TXL TXH TXM TXL
• • •
TXH TXM TXL
01 10 11 01 10 11 01 10 11
DSP56012
DMA CONTR
OLLER
2.
INITIALIZE DSP56012 HOST INTERF
A
CE.
—MODE 24 BIT DMA —HOST T
O
DSP
—USE INIT BIT
T
O
:
SET TXDE CLEAR HRDF LO
AD DMA COUNTER
5.
HOST IS FREE
T
O
PERFORM
O
THER
T
ASKS (i.e
., DSP
T
O
HOST
TRANSFER ON A POLLED BASIS).
8.
TERMINA
TE DMA CHANNEL.
9.
TERMINA
TE DSP DMA MODE BY
CLEARING HM1, HM0, AND
TREQ.
7.
DMA CONTR
OLLER INTERR
UPTS HOST
WHEN
TRANSFERS ARE DONE.
HOREQ
PIN
6.
DMA CONTR
OLLER PERFORMS READS
.
$0
INTERR
UPT
CONTR
OL
REGISTER (ICR)
4.
ASSER
T HOREQ
T
O
ST
AR
T DMA
TRANSFER.
interr
upt VECT
OR T
ABLE
3.
TELL DSP56012 —WHERE
T
O
ST
ORE D
A
T
A
(i.e
., PR
OGRAM
ADDRESS REGISTER R7). —ENABLE INTERR
UPT HRIE (CAN BE
DONE
WITH A HOST COMMAND).
1
HF1
HF0
1
0
70
1
0 6
5
432
1
0
INIT
HM1
HM0
TREQ
RREQ
0
HF3
HF2
HTIE
1
70
0
0 6
5
432
1
HCIE
HRIE
AA0343.11
Note: When using the SAI and DAX peripherals, do not use interrupt vector addresses P:$0040–$004A, $0050, $0052, and $0056.