Host Programmer Model
6
-26
DSP56303 User’s Manual
6.7.2
Command Vector Register (CVR)
The host processor uses the CVR, an 8-bit read/write register, to cause the DSP56303 to
execute an interrupt. The host command feature is independent of any of the data transfer
mechanisms in the HI08. It causes execution of any of the 128 possible interrupt routines in
the DSP core. Hardware, software, individual, and stop resets clear the CVR bits.
1
TREQ
0
Transmit Request Enable
Enables host requests via the host request (HREQ or HTRQ) signal when
the transmit data register empty (TXDE) status bit in the ISR is set. If
TREQ is cleared, TXDE interrupts are disabled. If TREQ and TXDE are
set, the host request signal is asserted.
TREQ and RREQ modes (HDRQ = 0)
TREQ
RREQ
HREQ Signal
0
0
No interrupts (polling)
0
1
RXDF request (interrupt)
1
0
TXDE request (interrupt)
1
1
RXDF and TXDE request (interrupts)
TREQ and RREQ modes (HDRQ = 1)
TREQ
RREQ
HTRQ Signal
HRRQ Signal
0
0
No interrupts
(polling)
No interrupts
(polling)
0
1
No interrupts
(polling)
RXDF request
(interrupt)
1
0
TXDE request
(interrupt)
No interrupts
(polling)
1
1
TXDE request
(interrupt)
RXDF request
(interrupt)
0
RREQ
0
Receive Request Enable
Controls the HREQ signal for host receive data transfers. RREQ enables
host requests via the host request (HREQ or HRRQ) signal when the
receive data register full (RXDF) status bit in the ISR is set. If RREQ is
cleared, RXDF interrupts are disabled. If RREQ and RXDF are set, the
host request signal (HREQ or HRRQ) is asserted.
7
6
5
4
3
2
1
0
HC
HV6
HV5
HV4
HV3
HV2
HV1
HV0
Figure 6-16. Command Vector Register (CVR)
Table 6-15. Interface Control Register (ICR) Bit Definitions (Continued)
Bit Number
Bit Name
Reset Value
Description
Summary of Contents for DSP56303
Page 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Page 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Page 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Page 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Page 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Page 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Page 320: ...Index 14 DSP56303 User s Manual ...