Data processing system with adjustable clocks for partitioned synchronous interfaces

• US 6,578,155 B1
• Filed: 03/16/2000
• Issued: 06/10/2003
• Est. Priority Date: 03/16/2000
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Smith, Jack R., Faucher, Marc R.
• Primary Examiner(s): BUTLER, DENNIS
• Application Number:
  US09/526,854
• Time in Patent Office: 1,181 Days
• Field of Search: 713/400, 713/401, 713/500, 713/501, 713/503, 713/601
• US Class Current: 713/501
• CPC Class Codes: G06F 1/08 Clock generators with changeable or programmable clock frequency

Abstract

A data processing system (20) having a synchronous interface and partitioned clock and I/O logic controller structure. The system includes a plurality of processing components (22), each having a plurality of I/O logic controllers (24). In addition, the system includes a plurality of clock sources (30) for providing clock signals and a plurality of multiplexers (36) connected to said plurality of clock sources and to at least two of said I/O logic controllers. The clock signals differ from one another in frequency or in skew, i.e., time delay. By appropriate control of clock select registers connected to the plurality of multiplexers, one of the plurality of clock signals from the clock sources may be provided to the two or more I/O logic controllers connected to a given multiplexer. This permits different groups of I/O logic controllers to receive different clock signals in parallel. As a consequence, the signal interface for the system is partitioned into multiple group with each group controlled by a separate clock.

Claims

1. A data processing system comprising:

a. a plurality of processing components, each connected to at least one other of said processing components;

b. a plurality of clock sources, each providing a clock signal;

c. a plurality of controllers associated with each of said processing components;

d. a plurality of clock select registers, each providing a clock select signal; and

e. a plurality of multiplexers, each connected to said plurality of clock sources, to two or more of said plurality of controllers, and to one of said clock select registers, each of said multiplexers providing as an output to said two or more of said plurality of controllers one of said clock signals in response to a clock select signal provided by said one clock select register.

2. A system according to claim 1, further including a plurality of communication lines, wherein each of said plurality of multiplexers is connected via one of said plurality of communication lines to said two or more of said plurality of controllers.

3. A system according to claim 2, wherein each one of said plurality of communication lines is uniquely connected to said two or more of said plurality of controllers.

4. A system according to claim 1, wherein at least one of said clock signals is offset in time from other ones of said clock signals.

5. A system according to claim 1, wherein at least one of said clock signals has a different frequency than other ones of said clock signals.

6. A system according to claim 1, the system having a communication sequence protocol and further including an archcomp register connected to each of said plurality of controllers for indicating if said plurality of processing components must comply with said communication sequence protocol.

7. A system according to claim 6, wherein each of said plurality of controllers includes an archcomp register.

8. A system according to claim 6, wherein said archcomp register is designed to be written, in response to an ARCHCOMP instruction in a first bus cycle, with a first value when compatibility is desired and with a second value when compatibility is not desired, and said archomp register is designed so that the one of said first value and said second value present in said archcomp register propagates, in response to said ARCHCOMP instruction in a second bus cycle, to said controllers connected to said archcomp register, further wherein said ARCHCOMP instruction is executed on said plurality of processing components.

9. A system according to claim 1, wherein said each of said plurality of clock select registers is designed to be uniquely written, in response to a WRCLK instruction in a first bus cycle, with a value indicating the one of said plurality of clock sources having a clock signal to be provided as an output from the one of said plurality of multiplexers to which said each clock select register is connected, and said clock select registers are designed so that said value propagates, in response to said WRCLK instruction in a second bus cycle to said multiplexer with which said each clock select register is connected, further wherein said WRCLK instruction is executed on said plurality of processing components.

10. A system according to claim 1, wherein said clock select register is designed so that contents thereof may be read via a RDCLK instruction.

11. A system according to claim 1, wherein each of said plurality of processing components has a plurality of pins via which data is input and output and each of said plurality of controllers controls said input and output of data for selected ones of said plurality of pins, further wherein said system includes means connected to said plurality of controllers for assigning said selected ones of said plurality of pins to associated ones of said plurality of controllers.

12. A system according to claim 1, further including a cross-bar switch connected to said plurality of controllers associated with one of said plurality of processing components and an I/O select register connected to said cross-bar switch for providing instructions defining operation of said cross-bar switch.

13. A system according to claim 12, wherein said system is designed to provide an IOSELECT instruction and said instructions in said I/O select register are determined by said IOSELECT instruction.

14. A method of providing clock signals in a data processing system having a plurality of processing components, each of the processing components including a plurality of pins for controlling input and output of data, and a plurality of controllers associated with the processing components, the method comprising the steps of

a. providing a plurality of different clock signals;

b. selecting one of said plurality of clock signals for each of said plurality of controllers; and

c. providing said selected ones of said plurality of clock signals to said plurality of controllers in parallel and assigning selected ones of said plurality of pins to associated ones of said plurality of processing components.