Stereo System User Manual

Parallel Host Interface
Host Interface (HI)
MOTOROLA DSP56012 User’s Manual 4-63
Figure 4-37 Host to DSP DMA Procedure
WRITE ICR
HOST PROCESSOR
X:$FFE8
HOST CONTROL REGISTER (HCR)
P:$007E
AVAILABLE FOR HOST COMMAND
FAST INTERRUPT
OR
LONG INTERRUPT
P:$0000
HOST TRANSMIT DATA VECTOR
P:$0032
1. PROGRAM DMA CONTROLLER.
—START ADDRESS —BYTE COUNT —TRANSFER DIRECTION —START DMA CHANNEL
TXH
TXM
TXL
TXH
TXM
TXL
• • •
TXH
TXM
TXL
01 10 11 01 10 11 01 10 11
DSP56012DMA CONTROLLER
2. INITIALIZE DSP56012 HOST INTERFACE.
—MODE 24 BIT DMA —HOST TO DSP —USE INIT BIT TO: SET TXDE CLEAR HRDF LOAD DMA COUNTER
5. HOST IS FREE TO PERFORM
OTHER TASKS (i.e., DSP TO HOST TRANSFER ON A POLLED BASIS).
8. TERMINATE DMA CHANNEL. 9. TERMINATE DSP DMA MODE BY CLEARING HM1, HM0, AND TREQ.
7. DMA CONTROLLER INTERRUPTS HOST
WHEN TRANSFERS ARE DONE.
HOREQ
PIN
6. DMA CONTROLLER PERFORMS READS.
$0
INTERRUPT CONTROL REGISTER (ICR)
4. ASSERT HOREQ TO START DMA TRANSFER.
interrupt VECTOR TABLE
3. TELL DSP56012
—WHERE TO STORE DATA (i.e., PROGRAM ADDRESS REGISTER R7). —ENABLE INTERRUPT HRIE (CAN BE DONE WITH A HOST COMMAND).
1 HF1 HF0 1 0
70
10
65432 1
0
INIT HM1 HM0 TREQ RREQ
0
HF3 HF2 HTIE 1
70
00
65432 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.