Microprocessor debugging mechanism employing scan interface
First Claim
1. Apparatus for carrying out debugging procedures on a processor, the processor including a chain of scan registers, scan interface means for interfacing with a scan controller means external of the processor, a breakpoint interrupt means for executing an interrupt instruction, and a processor clock control means wherein, when, in the operation of the microprocessor a breakpoint is detected or generated, the breakpoint interrupt means executes an interrupt, the microprocessor completes its current instruction and then branches to an Interrupt Service Vector, the completion of which is signalled to the scan interface means which provides a Start Scan signal to the clock control means, following which the scan interface means signals the external scan controller to begin a scanning operation.
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Abstract
In order to smooth the entry into a debugging operation using a scan chain of registers in a microprocessor, a method for carrying out debugging procedures. The method comprises providing a processor with a chain of scan registers, a scan interface for interfacing with an external scan controller, a breakpoint interrupt mechanism for executing an interrupt instruction, and a processor clock control mechanism. The method includes detecting or generating a breakpoint in the operation of the processor. The breakpoint interrupt mechanism executes an interrupt instruction as a result of which the processor completes its current instruction, and signals the same to the scan interface. The scan interface asserts a Start Scan signal to the clock signal control mechanism, which whereupon stops the processor clock or clocks. The external scan controller is alerted to start a scan sequence.
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Citations
11 Claims
- 1. Apparatus for carrying out debugging procedures on a processor, the processor including a chain of scan registers, scan interface means for interfacing with a scan controller means external of the processor, a breakpoint interrupt means for executing an interrupt instruction, and a processor clock control means wherein, when, in the operation of the microprocessor a breakpoint is detected or generated, the breakpoint interrupt means executes an interrupt, the microprocessor completes its current instruction and then branches to an Interrupt Service Vector, the completion of which is signalled to the scan interface means which provides a Start Scan signal to the clock control means, following which the scan interface means signals the external scan controller to begin a scanning operation.
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9. A method for carrying out debugging procedures on a processor, the method comprising the following steps:
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a. providing a processor with a chain of scan registers, a scan interface means for interfacing with an external scan controller means, a breakpoint interrupt means for executing an interrupt instruction, and a processor clock control means;
b. detecting or generating a breakpoint in the operation of the processor;
c. the breakpoint interrupt means executes an interrupt instruction as a result of which the processor completes its current instruction, and signals the same to the scan interface means;
d. the scan interface means asserts a Start Scan signal to the clock control means, which whereupon stops the processor clock or clocks; and
e. the external scan controller means is alerted to start a scan sequence. - View Dependent Claims (10, 11)
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Specification