Configuring Interrupts
4
-20
DSP56303 User’s Manual
The DSP56303 has a four-level interrupt priority structure. Each interrupt has two interrupt
priority level bits (IPL[1–0]) that determine its interrupt priority level. Level 0 is the lowest
priority; Level 3 is the highest-level priority and is non-maskable. Table 4-4 defines the IPL
bits.
The IPRC also selects the trigger mode of the external interrupts (
IRQA
–
IRQD
). If the value of
the IxL2 bit is 0, the interrupt mode is level-triggered. If the value is 1, the interrupt mode is
negative-edge-triggered.
4.4.2
Interrupt Table Memory Map
Each interrupt is allocated two instructions in the interrupt table, resulting in 128 table entries
for interrupt handling. Table 4-5 shows the table entry address for each interrupt source. The
DSP56303 initialization program loads the table entry for each interrupt serviced with two
interrupt servicing instructions. In the DSP56303, only some of the 128 vector addresses are
used for specific interrupt sources. The remaining interrupt vectors are reserved and can be
used for host
NMI
(IPL = 3) or for host command interrupt (IPL = 2). Unused interrupt vector
locations can be used for program or data storage.
Table 4-4. Interrupt Priority Level Bits
IPL bits
Interrupts Enabled
Interrupts Masked
Interrupt Priority Level
xxL1
xxL0
0
0
No
—
0
0
1
Yes
0
1
1
0
Yes
0, 1
2
1
1
Yes
0, 1, 2
3
Table 4-5. Interrupt Sources
Interrupt
Starting Address
Interrupt
Priority Level
Range
Interrupt Source
VBA:$00
3
Hardware RESET
VBA:$02
3
Stack error
VBA:$04
3
Illegal instruction
VBA:$06
3
Debug request interrupt
VBA:$08
3
Trap
VBA:$0A
3
Nonmaskable interrupt (NMI)
VBA:$0C
3
Reserved
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 ...