Reduced instruction set baseboard controller
In wireless communications such as in the Bluetooth communication system, an execution unit sequentially receives software instructions for execution. Prior to completing each instruction, the execution unit issues an interrupt indicating the upcoming completion of the instruction execution and awaits receipt of the next instruction. A Link Manager issues limited instructions, and a Link Controller includes a hardware execution unit for executing the limited instructions. A processing unit in the Link Manager performs remaining functions under control of a software program.
1. A method of operating a Bluetooth device, comprising:
issuing a first software instruction to an execution unit;
executing the first software instruction using the execution unit;
completing the execution of the first software instruction; and
prior to completing the execution of the first software instruction, issuing an interrupt from the execution unit indicating the upcoming completion of the execution of the first software instruction.
2. The method of claim 1 wherein the interrupt is issued about 300 μs before completion of the execution of the first software instruction.
3. The method of claim 1 further comprising:
issuing a second software instruction prior to completing the execution of the first software instruction; and
executing the second software instruction immediately upon completing the execution of the first software instruction.
4. A method of issuing instructions to an execution unit, comprising:
issuing a first instruction to the execution unit;
executing the first instruction using the execution unit;
completing the execution of the first instruction;
prior to completing the execution of the first instruction, issuing an interrupt from the execution unit indicating the upcoming completion of execution of the first instruction; and
issuing a second instruction in response to the interrupt.
5. The method of claim 4 , wherein the first instruction is issued to a first instruction register and the second instruction is issued to a second instruction register.
6. The method of claim 4 , wherein the first instruction register and the second instruction register are included in an instruction register stack.
7. The method of claim 4 , further comprising:
issuing a second interrupt if said second instruction has not been issued prior to completing the execution of the first instruction.
8. A system to execute instructions in a Bluetooth device comprising:
an instruction stack;
a link controller coupled to the instruction stack and enabled to execute instructions from the instruction stack;
a link manager coupled to the instruction stack and the instruction execution unit and enabled to write instructions to the instruction stack;
wherein the link controller issues a request for an instruction to the link manager prior to completing execution of a first instruction; and
wherein the link manager writes an instruction into the instruction stack in response to the request from the link controller.
9. The system of claim 8 , wherein the link controller issues a first interrupt to request an instruction from the link manager.
10. The system of claim 9 , wherein the first interrupt includes one or more error indicators.
11. The system of claim 10 , wherein the error indicators include one or more of check sum error, absence of correlation error, incorrect address error and incorrect sequence error.
12. The system of claim 9 , wherein the first interrupt is issued approximately 300 us before the completion of execution of the first instruction.
13. The system of claim 9 , wherein the link controller is enabled to issue a second interrupt if the link manager fails to write an instruction to the instruction stack after receiving the first interrupt.
14. The system of claim 8 , wherein the link controller is enabled to issue an interrupt to the link manager that indicates availability of data in a read buffer.
15. The system of claim 8 , wherein the link controller is enabled to issue an interrupt to the link manager that indicates that a received data packet has an incorrect Cyclic Redundancy Check (CRC) code.
16. The system of claim 8 , wherein the link controller is enabled to execute an instruction multiple times based on a bit value in a particular field of an instruction.
17. The system of claim 16 , wherein writing a specified bit in a particular register causes termination of execution of an instruction being executed multiple times by the link controller.