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MCF5272 User’s Manual
Processor Status, DDATA Definition
bus. The processor responds by stalling the instruction fetch pipeline and waiting for
current bus activity to complete before freeing the local bus for the debug module to
perform its access. After the debug module bus cycle, the processor reclaims the bus.
Breakpoint registers must be carefully configured in a development system if the processor
is executing. The debug module contains no hardware interlocks, so TDR should be
disabled while breakpoint registers are loaded, after which TDR can be written to define the
exact trigger. This prevents spurious breakpoint triggers.
Because there are no hardware interlocks in the debug unit, no BDM operations are allowed
while the CPU is writing the debug’s registers (DSCLK must be inactive).
Note that the debug module requires the use of the internal bus to perform BDM
commands. In Revision A, if the processor is executing a tight loop that is contained within
a single aligned longword, the processor may never grant the internal bus to the debug
module, for example:
align4
label1: nop
bra.b label1
or
align4
label2: bra.w label2
The processor grants the internal bus if these loops are forced across two longwords.
5.7 Processor Status, DDATA Definition
This section specifies the ColdFire processor and debug module’s generation of the
processor status (PST) and debug data (DDATA) output on an instruction basis. In general,
the PST/DDATA output for an instruction is defined as follows:
PST = 0x1, {PST = [0x89B], DDATA= operand}
where the {...} definition is optional operand information defined by the setting of the CSR.
The CSR provides capabilities to display operands based on reference type (read, write, or
both). A PST value {0x8, 0x9, or 0xB} identifies the size and presence of valid data to
follow on the DDATA output {1, 2, or 4 bytes}. Additionally, for certain change-of-flow
branch instructions, CSR[BTB] provides the capability to display the target instruction
address on the DDATA output {2, 3, or 4 bytes} using a PST value of {0x9, 0xA, or 0xB}.
5.7.1 User Instruction Set
Table 5-22 shows the PST/DDATA specification for user-mode instructions. Rn represents
any {Dn, An} register. In this definition, the ‘y’ suffix generally denotes the source and ‘x’
denotes the destination operand. For a given instruction, the optional operand data is
displayed only for those effective addresses referencing memory.The ‘DD’ nomenclature
refers to the DDATA outputs.
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...