Parallel Host Interface
Host Interface (HI)
MOTOROLA
DSP56012 User’s Manual
4-41
4.4.7.5
Servicing DMA Interrupts
When HM0
≠
0 and/or HM1
≠
0, HOREQ will be asserted to request a DMA
transfer. Generally the HOREQ pin will be connected to the REQ input of a DMA
controller. The HOA[2:0], HR/W, and HEN pins are not used during DMA transfers;
DMA transfers only use the HOREQ and HACK pins after the DMA channel has
been initialized. HACK is used to strobe the data transfer, as shown in
Figure 4-17
on page 4-41 where an MC68440 is used as the DMA controller. DMA transfers to
and from the HI are presented in more detail in
Section
4.4.8 Host Interface
Application Examples
.
Figure 4-17 DMA Transfer Logic and Timing
DMA ACK Gated Off
Fast Interrupt
To Transfer 24-bit Word
High
Byte
MC68440
IRQ
ACK0
+5 V
DSP56012
To IRQB
+5 V
+5 V
HOREQ
HACK
REQ0
CI
Q
D
Burst
REQ0
HACK
High
Byte
Middle
Byte
Low
Byte
1 DMA Cycle = 8T = 4 DMA Clock Cycles
Max. MC68440 Clock = 10 MHz = > T = 50 ns
8T
A0
A1
AS
OWN
AA0325k
Summary of Contents for DSP56012
Page 12: ...xii Motorola ...
Page 20: ...xx Motorola ...
Page 21: ...MOTOROLA DSP56012 User s Manual 1 1 SECTION 1 OVERVIEW ...
Page 40: ...1 20 DSP56012 User s Manual MOTOROLA Overview DSP56012 Architectural Overview ...
Page 41: ...MOTOROLA DSP56012 User s Manual 2 1 SECTION 2 SIGNAL DESCRIPTIONS ...
Page 61: ...SECTION 3 MEMORY OPERATING MODES AND INTERRUPTS ...
Page 81: ...MOTOROLA DSP56012 User s Manual 4 1 SECTION 4 PARALLEL HOST INTERFACE ...
Page 148: ...4 68 DSP56012 User s Manual MOTOROLA Parallel Host Interface Host Interface HI ...
Page 149: ...MOTOROLA DSP56012 User s Manual 5 1 SECTION 5 SERIAL HOST INTERFACE ...
Page 179: ...MOTOROLA DSP56012 User s Manual 6 1 SECTION 6 SERIAL AUDIO INTERFACE ...
Page 205: ...MOTOROLA DSP56012 User s Manual 7 1 SECTION 7 GPIO ...
Page 210: ...7 6 DSP56012 User s Manual MOTOROLA GPIO GPIO Register GPIOR ...
Page 211: ...MOTOROLA DSP56012 User s Manual 8 1 SECTION 8 DIGITAL AUDIO TRANSMITTER ...
Page 226: ...8 16 DSP56012 User s Manual MOTOROLA Digital Audio Transmitter DAX Programming Considerations ...
Page 233: ...MOTOROLA DSP56012 User s Manual B 1 APPENDIX B PROGRAMMING REFERENCE ...