Stereo System User Manual

Parallel Host Interface
Host Interface (HI)
MOTOROLA DSP56012 User’s Manual 4-57
Figure 4-32 Bits Used for DSP to Host Transfer
HOST DSP56012
RXDF—RECEIVE DATA REGISTER FULL
1 = INDICATES THE RECIEVE BYTE REGISTERS (RXH, RXM, RXL) CONTAIN DATA FROM THE DSP. 0 = CLEARED BY READING RXL.
HTDE—HOST TRANSMIT DATA EMPTY
1 = HOTX IS EMPTY AND CAN BE WRITTEN BY DSP. 0 = HOTX IS FULL.
HTIE—HOST TRANSMIT INTERRUPT ENABLE
1 = ENABLE THE DSP INTERRUPT TO P:$0032. 0 = DISABLE THE DSP INTERRUPT TO P:$0032.
DSP INTERRUPT IS CAUSED BY HTDE = 1
RREQ —RECEIVE REQUEST ENABLE (USED TO CONTROL THE HOREQ PIN)
1 = ENABLE INTERRUPT REQUESTS CREATED BY RXDF. 0 = DISABLE INTERRUPT REQUESTS.
$2
INTERRUPT STATUS REGISTER (ISR) (READ ONLY)
$0
X:$FFE8
HOST STATUS REGISTER (HSR) (READ ONLY) HOST CONTROL REGISTER (HCR) (READ/WRITE)
INTERRUPT CONTROL REGISTER (ICR) (READ/WRITE)
X:$FFE8
HOREQ
HF3 HF2 TXDE RXDF
70
0DMA
65432 1
TRDY DMA HF1 HF0 HTDE HRDF
70
00
65432 1
HCP
INIT
HF1 HF0 TREQ RREQ
70
HM0HM1
65432 1
00HF3 HF2 HTIE HRIE
70
00
65432 1
HCIE
MODES
AA0339