Host Interface (HDI08)
Servicing The Host Interface
MOTOROLA
DSP56367
8-31
5. If HREQ=1, the HOREQ/HTRQ/HRRQ signal has been asserted, and the DSP is
requesting the attention of the host processor. One of the previous four conditions
exists.
After the appropriate data transfer has been made, the corresponding status bit is updated to
reflect the transfer.
If the host processor has issued a command to the DSP by writing the CVR and setting the HC
bit, it can read the HC bit in the CVR to determine when the command has been accepted by
the interrupt controller in the DSP core. When the command has been accepted for execution,
the HC bit is cleared by the interrupt controller in the DSP core.
Figure 8-16 HDI08 Host Request Structure
8.7.3
SERVICING INTERRUPTS
If either the HOREQ/HTRQ or the HRRQ signal or both are connected to the host processor
interrupt inputs, the HDI08 can request service from the host processor by asserting one of
these signals. The HOREQ/HTRQ and/or the HRRQ signal is asserted when TXDE=1 and/or
RXDF=1 and the corresponding enable bit (TREQ or RREQ, respectively) is set. This is
depicted in Figure 8-16.
HOREQ/HTRQ and HRRQ are normally connected to the host processor maskable interrupt
inputs. The host processor acknowledges host interrupts by executing an interrupt service
routine. The host processor can test RXDF and TXDE to determine the interrupt source. The
host processor interrupt service routine must read or write the appropriate HDI08 data register
to clear the interrupt. HOREQ/HTRQ and/or HRRQ is deasserted under the following
conditions:
7
0
HREQ
0
0
HF3
HF2
TRDY
TXDE
RXDF
STATUS
ISR
INIT
0
HLEND
HF1
HF0
HDRQ
TREQ
RREQ
7
0
$0
ICR
ENABLE
Host Request
ASSERTED
HOREQ
HRRQ
HTRQ
$2
Summary of Contents for DSP56367
Page 16: ...xvi MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 22: ...xxii MOTOROLA List of Figures Figure Number Title Page Number ...
Page 26: ...xxvi MOTOROLA List of Tables Table Number Title Page Number ...
Page 148: ...4 6 DSP56367 MOTOROLA Design Considerations PLL Performance Issues ...
Page 248: ...9 30 DSP56367 MOTOROLA Serial Host Interface SHI Programming Considerations ...
Page 306: ...10 58 DSP56367 MOTOROLA Enhanced Serial Audio Interface ESAI ESAI Initialization Examples ...
Page 389: ...Bootstrap ROM Contents MOTOROLA DSP56367 A 15 end ...
Page 390: ...A 16 DSP56367 MOTOROLA Bootstrap ROM Contents ...
Page 432: ...C 8 DSP56367 MOTOROLA JTAG BSDL ...
Page 484: ...D 52 DSP56367 MOTOROLA Programmer s Reference ...
Page 490: ...E 6 DSP56367 MOTOROLA Power Consumption Benchmark ...
Page 516: ...F 26 DSP56367 MOTOROLA IBIS Model ...
Page 522: ...Index 6 MOTOROLA Index ...
Page 523: ......