Patent ID: 6314486
Filing Date: 2001-11-06
Classification: G06F

Abstract:
A method for accessing a plurality of control and status registers for a device within a computer system, the plurality of control and status registers being used to configure the device and to read status information from the device, the method comprising:serially shifting an index into an index register within the device, the index specifying a register to be accessed from the plurality of control and status registers;during a write operation to the register to be accessed,serially shifting a data value into a data register within the device, andmoving the data value from the data register into the register to be accessed; andduring a read operation from the register to be accessed,loading a value into the data register from the register to be accessed, andserially shifting the value from the data register to a location outside the device to complete the read operation;wherein the act of serially shifting the index and the act of serially shifting the data value take place through separate loops maintained by a JTAG controller; andwherein the index register is a register different from the data register.