MC68020FE25E Freescale Semiconductor, MC68020FE25E Datasheet - Page 186

• Manufacturer Part Number: MC68020FE25E
• Description: IC MICROPROCESSOR 32BIT 132CQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68020FE25E

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-CQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

and PF = 1, and then performs trace exception processing. When IA = 1, the main
processor services pending interrupts before reading the response CIR again.
A coprocessor can be designed to execute a cpGEN instruction concurrently with the
execution of main processor instructions and, also, buffer one write operation to either its
command or condition CIR. This type of coprocessor issues a null primitive with CA = 1
when it is concurrently executing a cpGEN instruction, and the main processor initiates
another general or conditional coprocessor instruction. This primitive indicates that the
coprocessor is busy and the main processor should read the response CIR again without
reinitiating the instruction. The IA bit of this null primitive usually should be set to minimize
interrupt latency while the main processor is waiting for the coprocessor to complete the
general category instruction.
Table 7-3 summarizes the encodings of the null primitive.
x = Don't Care
c = 1 or 0 Depending on Coprocessor Condition Evaluation
MOTOROLA
CA
x
1
1
0
0
0
PC
1
0
0
0
0
0
IA
x
0
1
0
1
x
Table 7-3. Null Coprocessor Response Primitive Encodings
PF
x
x
x
0
0
1
TF
x
x
x
c
c
c
Pass Program Counter to Instruction
Address CIR, Clear PC Bit, and Proceed
with Operation Specified by CA, IA, PF,
and TF Bits
Reread Response CIR, Do Not Service
Pending Interrupts
Service Pending Interrupts and Reread the
Response CIR
If (Trace Pending) Reread Response CIR;
Else, Execute Next Instruction
If (Trace Pending) Service Pending
Interrupts and Reread Response CIR;
Else, Execute Next Instruction
Coprocessor Instruction Completed;
Service Pending Exceptions or Execute
Next Instruction
Freescale Semiconductor, Inc.
For More Information On This Product,
General Instructions
Go to: www.freescale.com
M68020 USER’S MANUAL
Same as General Category
Same as General Category
Same as General Category
Main Processor Completes Instruction
Execution Based on TF = c
Main Processor Completes Instruction
Execution Based on TF = c
Main Processor Completes Instruction
Execution Based on TF = c.
Conditional Instructions
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