Implementation Of The Pc Trace Function; Implementation Of The Bus Trace Function - Epson S5U1C33001H1400 Manual

10.4 Implementation of the PC trace function

The PC trace function is implemented by a method that allows the debugger (gdb.exe) to analyze the
target program flow using the information delivered on the DST0, DST1, DST2 and DPCO signals
output from the S1C33xxx chip, and the target program information loaded into the debugger. The
debugger obtains the absolute addresses information required for analyzing the target program flow
from the following status.
(1) The PC (program counter) value when the target program restarts executing from suspended
status
(2) Trace trigger set-up address when a trace trigger is generated
(3) The PC (program counter) value that is output on the 27- or 31-cycle DPCO signal (PC signal
for debugging)
Furthermore, target program execution information is output on the DST0–DST2 signals (status
signals for debugging). The debugger analyzes execution and branches successively using this
absolute address and execution information, and displays the trace information. Therefore, there are
some restrictions in the PC trace function. For details on the PC trace function and operating
procedures, see the "Debugger" section in the "S5U1C33001C Manual (C Compiler Package for
S1C33 Family)".

10.5 Implementation of the bus trace function

The S1C33xxx bus trace function monitors the internal bus to obtain the bus address, data, bus
master, read/write, access size and access type (instruction fetch cycle or data access cycle)
information when a read or write access is generated. The sampled information is divided and output
from the DST4-0 and DTD7-0 pins to the S5U1C33001H in maximum 8 cycles. If a new bus access
is generated while the current bus information is being output from the target system, the S1C33xxx
will suspend outputting the current trace information and will start outputting the new trace
information. Therefore, frequent bus accesses reduce bus trace information to be obtained. In this
case, select a bus trace option for compressing the trace data. The information compress circuit in the
S1C33xxx compresses the bus trace data before outputting, thus the amount of bus trace information
that can be obtained will be increased.
Furthermore, the items to be traced can be narrowed by specifying a command parameter so that the
desired bus trace information to be obtained will be increased.
The bus trace function does not affect the real-time program execution.
S1C33 Family In-Circuit Debugger
S5U1C33001H1400 Manual (Rev. 0.20)
EPSON
10. PRECAUTIONS
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