AN2108 Freescale Semiconductor / Motorola, AN2108 Datasheet - Page 18

• Manufacturer Part Number: AN2108
• Description: AN2108 Programming the DSP56307/DSP56311 EFCOP in C Using Taskings Tool Suite
• Manufacturer: Freescale Semiconductor / Motorola

18
Transferring Data to and from the EFCOP
VBA + $6A
VBA + $68
Table 5 and Table 6 list the priorities corresponding to these settings.
In the vectored interrupt architecture of the DSP56307, up to 128 interrupt sources cause the processor to
jump to one of 128 program addresses. These addresses are two words apart, so if the interrupt can be
serviced using only two words of machine code, there is no need to jump to a larger interrupt service
routine. These interrupts are called fast interrupts. In many cases, however, the interrupt requires more
than two words of code. In these cases, the two words in the interrupt vector space contain a JMP
instruction to the location of the interrupt service routine. These interrupts are called long interrupts.
The actual address of a particular interrupt vector consists of the Vector Base Address (VBA), which is
stored in the VBA register, plus an offset corresponding to the particular interrupt source. For example, the
offset when the EFCOP Data Input Buffer is empty (FDIBE) is $68, and the offset when the EFCOP Data
Output Buffer is full (FDOBF) is $6A. The addresses are therefore VBA + $68 and VBA + $6A,
respectively [4].Table 7 shows the interrupt vectors for the EFCOP on the DSP56307.
Interrupt
Address
Interrupt
Number
E0L1=IPRP[10]
52
53
I1 = SR[8]
Programming the DSP56307/DSP56311 EFCOP in C
0
0
1
1
0
0
1
1
Freescale Semiconductor, Inc.
Table 6. EFCOP Interrupt Priority Levels.
Table 5. Status Register Interrupt Masks
Data input buffer empty
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Data output buffer full
Table 7. EFCOP Interrupt Vectors
Interrupt Vector
E0L0=IPRP[11]
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I0=SR[9]
0
1
0
1
0
1
0
1
IPL 0,1,2,3
IPL 1,2,3
IPL 2,3
IPL 3
Priority
IPL0
IPL1
IPL2
IPL3
0–2
0–2
EFCOP Interrupt Priority
Interrupt Priority Level
Exceptions Permitted
Level
FDOIE=FCSR[11]
Interrupt Enable
FDIIE=FCSR[10]
Conditions
FDOBF=1
Interrupt
FDIBE=1