Electrical computers and digital data processing systems: input/ – Input/output data processing – Peripheral monitoring
Reexamination Certificate
1999-06-18
2001-03-27
Lee, Thomas C. (Department: 2782)
Electrical computers and digital data processing systems: input/
Input/output data processing
Peripheral monitoring
C709S208000, C714S034000
Reexamination Certificate
active
06209045
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to data processors including microcomputers, digital signal processors, microcontrollers and microprocessors especially with debug support features such as emulation. More particularly, the invention relates to a data processor for debugging a microcomputer-based system in a real-use operation environment such as outdoors.
The microcomputer-based system (also called the target system) may be debugged by means of a microcomputer for evaluation use with debug support features. In interfacing the evaluation-use microcomputer to a debugging host system, a large number of signal lines may be used to transmit in parallel data, addresses and control signals equivalent to those of the interface between the microcomputer in question and the target system. However, where the target- system is appreciably small in volume as in the case of a portable communication terminal, it is often impossible practically to equip the circuit board of the system with pins or connectors for connecting numerous signal lines.
One proposed solution to such a bottleneck is the use of a serial interface with the debugging host system. Technical aspects of the solution are discussed illustratively in “DSP 96002 User's Manual” (SECTION 10, ON-CHIP EMULATOR; p10-1~p10-22).
The technique described in the publication above involves incorporating in a digital signal processor a command decoder and a break point control circuit for debugging purposes as well as a serial interface for debug use which allows data to be input and output serially in synchronism with a clock signal. Debug commands are fed externally to the processor through the serial interface. The command decoder decodes the commands thus supplied. The decoded result is referenced in controlling write and read operations to and from internal registers as well as in controlling break points.
SUMMARY OF THE INVENTION
With the conventional technique outlined above, the debug command functions are predetermined fixedly and are thus limitative of the degree of flexibility with which to set simulated internal states for a data processor or to reference internal states of the data processor for debugging purposes. Given the fact that data processors such as digital signal processors are adapted extensively to various data processing systems, the debug support features thus restricted are not quite convenient to use. In other words, debug operations lack variability.
Adopting the above-mentioned serial interface reduces the number of connectors for connection with the debugging host system. However, to minimize the number of signals requires reevaluating the control techniques of handshaking for asynchronous serial data input and output between the data processor in question and its external environment.
It is therefore an object of the present invention to provide a data processor capable of minimizing the number of signal terminals for debugging.
It is another object of the invention to provide a data processor allowing debug operations to be varied easily.
It is a further object of the invention to provide a data processor that permits debugging in an environment close to the real-use condition in which a target machine (i.e., product system) will be operating, and to provide a data processing system that utilizes such a data processor.
These and other objects, features and advantages of the invention will become more apparent upon a reading of the following description and appended drawings.
In carrying out the invention and according to one aspect thereof, there is provided as outlined in
FIG. 1
a data processor
1
formed on a semiconductor chip id comprising a central processing unit
10
, storage means
11
accessible by the central processing unit
10
, an interrupt controller
12
for controlling interrupts to the central processing unit
10
, serial interface means
15
for outputting and inputting data serially to and from the outside of the data processor
1
, and an internal bus
16
for connecting these component means and units. The storage means
11
includes a rewritable first storage area
111
and a second storage area
112
holding a boot program for causing the central processing unit
10
to transfer data from the serial interface means
15
to the first storage area
111
. The serial interface means
15
receives and decodes a first command (SDI boot command) from the outside, and outputs a first interrupt request signal (SDI_boot) to the interrupt controller
12
in accordance with the decoded first command. The interrupt controller
12
supplies the central processing unit
10
with first interrupt control data for executing the boot program in response to the first interrupt request signal.
When a system to which the data processor is applied (i.e., target system) is subjected to software or system debugging, a user program to be debugged is executed by the data processor. The data acquired from execution of the program is referenced externally when the user program is traced for debugging through its execution. Where any data arising from user program execution needs to be referenced from the outside or where desired operating conditions are to be set for the user program, it is necessary for the data processor to execute a debug control program different from the user program. The boot program mentioned above is a program that causes the central processing unit to download such a debug control program to an area different from a user program storage area. An appropriate debug control program may be prepared beforehand as needed depending on the constitution of the system to be debugged. In operation, the host system issues the first command mentioned above to the serial interface means. This causes the data processor to start the boot program, downloading the debug control program from the serial interface means to the first storage area. That is, when data coming out of the process of user program execution is to be referenced externally or when desired operating conditions are to be set for the user program, all operations involved are performed under control of the downloaded debug control program. Because all debug operations are carried out as per the suitably prepared debug control program, the variability of debug operations is guaranteed. Debug operations by the data processor are in no way limited because of the types of commands that may be accepted by the serial interface means.
The serial interface means for interfacing with the host system reduces the number of interface terminals for debugging purposes. Under such constraints, both the variability of debug operations and the ease of use are still ensured by the inventive data processor.
Where the target system is a portable communication terminal or a similar device to be carried around, it may be desired to subject the target system to system or software debugging in an outdoor setup approximating the actual use environment. Such debugging conditions are readily met by the data processor with its reduced number of interfacing terminals for debug use together with its enhanced debug operation versatility and ease of use.
In one preferred structure according to the invention, the second storage area may include a region
112
A accommodating a first vector used by the central processing unit to acquire a starting instruction address of the boot program upon receipt of the first interrupt control data.
In another preferred structure according to the invention, the boot program may include, at the end thereof, an instruction for causing instruction execution of the central processing unit to branch to a predetermined address of the debug control program transferred to the first storage area. This feature makes it possible automatically to activate the downloaded debug control program, thereby starting initial control operations immediately.
Illustratively, where one such initial control operation is the downloading of a user program to be debugged, the storage means may have a rewritable third storage area
Hasegawa Hironobu
Sasaki Hiroyuki
Uraguchi Masahiko
Elamin Abdelmoniem
Hitachi , Ltd.
Lee Thomas C.
Mattingly Stanger & Malur, P.C.
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