Section 20 User Break Controller (UBC)
20.1
Overview
The user break controller (UBC) provides functions that simplify program debugging. When break
conditions are set in the UBC, a user break interrupt is generated according to the contents of the
bus cycle generated by the CPU. This function makes it easy to design an effective self-
monitoring debugger, enabling programs to be debugged with the chip alone, without using an in-
circuit emulator.
20.1.1 Features
The UBC has the following features.
•
Two break channels (A and B)
User break interrupts can be generated on independent conditions for channels A and B, or on
sequential conditions (sequential break setting: channel A → channel B).
•
The following can be set as break compare conditions:
Address (selection of 32-bit virtual address and ASID for comparison):
Address: All bits compared/lower 10 bits masked/lower 12 bits masked/lower 16 bits
masked/lower 20 bits masked/all bits masked
ASID: All bits compared/all bits masked
Data (channel B only, 32-bit mask capability)
Bus cycle: Instruction access/operand access
Read/write
Operand size: Byte/word/longword/quadword
An instruction access cycle break can be effected before or after the instruction is executed.
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Rev. 6.0, 07/02, page 773 of 986
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