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Chapter 20 Debug (S12XDBGV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
792 Freescale Semiconductor
20.1.2 Features
• Four comparators (A, B, C, and D):
— Comparators A and C compare the full address and the full 16-bit data bus
— Comparators A and C feature a data bus mask register
— Comparators B and D compare the full address bus only
— Each comparator can be configured to monitor either CPU or XGATE busses
— Each comparator features control of R/W and byte/word access cycles
— Comparisons can be used as triggers for the state sequencer
• Three comparator modes:
— Simple address/data comparator match mode
— Inside address range mode, Addmin ≤ Address ≤ Addmax
— Outside address range match mode, Address < Addmin or Address > Addmax
• Two types of triggers:
— Tagged: triggers just before a specific instruction begins execution
— Force: triggers on the first instruction boundary after a match occurs.
• Three types of breakpoints:
— CPU breakpoint entering BDM on breakpoint (BDM)
— CPU breakpoint executing SWI on breakpoint (SWI)
— XGATE breakpoint
• Three trigger modes independent of comparators:
— External instruction tagging (associated with CPU instructions only)
— XGATE S/W breakpoint request
— TRIG bit immediate software trigger
• Three trace modes:
— Normal: change of flow (COF) bus information is stored (see Section 20.4.5.2.1, “Normal
Mode”) for change of flow definition.
— Loop1: same as normal but inhibits consecutive duplicate source address entries
— Detail: address and data for all cycles except free cycles and opcode fetches are stored
• 4-stage state sequencer for trace buffer control:
— Tracing session trigger linked to final state of state sequencer
— Begin, end, and mid alignment of tracing to trigger
20.1.3 Modes of Operation
The DBG module can be used in all MCU functional modes.
During BDM hardware accesses and when the BDM module is active, CPU monitoring is disabled. Thus
breakpoints, comparators and bus tracing mapped to the CPU are disabled but accessing the DBG registers,
including comparator registers, is still possible. While in active BDM or during hardware BDM accesses,