摘要:
The logic circuitry of an IC chip is connected to JTAG register chains which hold state information on each portion of the logic circuitry therein. A JTAG Tracker Module is connected to the controls of each of the JTAG register chains enabling a programmer-operator to read the present state of each JTAG register chain and enabling a readout of the logic circuits condition in a single clock period.
摘要:
An error logging system where errors are captured on dual system busses operating at a lower clock rate (16 MHz) than the processor which receives the error information. The system functions to substantially reduce the loads on the processor in addition to maximizing the use of the system bus drivers which are pin-constrained. The processor operates at a higher clock rate (32 MHz). Processor commands to read error data from an error log register are synchronized down to the 16 MHz rate, then enabled onto a processor bus after a second synchronization operation back to the higher (32 MHz) rate. Provision is made for identifying several different types of error categories. An expandable error log register system is provided which uses selected bit positions to identify types of errors logged to the processor which also enables expansitivity for adding in future types of errors into the error logging system and renders compatibility for a processor operating at first clock rate with error data sensed at a second clock rate.
摘要:
A single chip data path gate array interface links a central processing unit, operating at a first clock rate and single word protocol, to dual system busses operating at a second clock rate and multiple-word protocol. The data path interface holds command, data and message registers, controlled by external logic, in an input channel pathway and an output channel pathway. The interface chip is basically limited to registers and multiplexers making it flexible for use in different architectures such as both Store-Through and Non-Store-Through cache protocols. In addition, such a simplified chip is simple to fabricate and to maintain free of defects.