Abstract: A data processing system (100, 300) allows an individually mappable word of memory to patch a desired memory location. During operation, a memory system (130) monitors an address/control bus to determine when an access to a specified word in a system memory (120) occurs. When an access to the specified word occurs, address comparators (140) determine if a memory location to be patched is being accessed, and provides an active signal to the access control circuit (150), which prevents data flow with the system memory (120) and enables the data flow with a separate memory (170) by controlling a transmission gate 115. Therefore, the data access occurs from the separate memory and not the system memory.

Abstract: An integrated circuit terminal of a data processing system (10) is used to communicate multiplexed signals with an external device. During a reset operation in which a reset signal is asserted, a desired internal clock signal is driven to the integrated circuit terminal such that an emulation system (52) may use the internal clock signal to synchronize an emulation operation. After the reset signal is negated, the emulation system synthesizes the internal clock signal for use during emulation. External visibility of a write operation to a register which controls pertinent signal parameters is provided via other integrated circuit terminals when the data processor operates in an emulation mode. The external visibility allows the development system to make similar changes to corresponding signal parameters therein. Therefore, the development system is able to accurately synchronize an emulation operation even when signal parameters are modified during operation.

Abstract: A data processor (10) and method which provides show-cycles on a fast multiplexed bus (28) using two distinct modes of operation. A first mode of operation supports a standard show-cycle on a multiplexed bus for interface to a passive device such as a logic analyzer (100). A second mode of operation supports emulation tools (100) with real-time tracking of control functions using a multiplexed bus. During each of the modes of operation of the data processor (10), both read and write show cycles are supported and are consistently provided in a similar format.