Nxp Semiconductors LPC2194HBD64,151 ARM7 Microcontroller 16kB LQFP 64 LPC2194HBD64,151 数据表

LPC2194_4

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The LPC2194 support emulation and debugging via a JTAG serial port. A trace port allows 
tracing program execution. Debugging and trace functions are multiplexed only with 
GPIOs on Port 1. This means that all communication, timer and interface peripherals 
residing on Port 0 are available during the development and debugging phase as they are 
when the application is run in the embedded system itself.

Standard ARM EmbeddedICE logic provides on-chip debug support. The debugging of 
the target system requires a host computer running the debugger software and an 
EmbeddedICE protocol convertor. EmbeddedICE protocol convertor converts the Remote 
Debug Protocol commands to the JTAG data needed to access the ARM core.

The ARM core has a Debug Communication Channel function built-in. The debug 
communication channel allows a program running on the target to communicate with the 
host debugger or another separate host without stopping the program flow or even 
entering the debug state. The debug communication channel is accessed as a 
co-processor 14 by the program running on the ARM7TDMI-S core. The debug 
communication channel allows the JTAG port to be used for sending and receiving data 
without affecting the normal program flow. The debug communication channel data and 
control registers are mapped in to addresses in the EmbeddedICE logic.

Since the LPC2194 have significant amounts of on-chip memory, it is not possible to 
determine how the processor core is operating simply by observing the external pins. The 
ETM provides real-time trace capability for deeply embedded processor cores. It outputs 
information about processor execution to the trace port.

The ETM is connected directly to the ARM core and not to the main AMBA system bus. It 
compresses the trace information and exports it through a narrow trace port. An external 
trace port analyzer must capture the trace information under software debugger control. 
Instruction trace (or PC trace) shows the flow of execution of the processor and provides a 
list of all the instructions that were executed. Instruction trace is significantly compressed 
by only broadcasting branch addresses as well as a set of status signals that indicate the 
pipeline status on a cycle by cycle basis. Trace information generation can be controlled 
by selecting the trigger resource. Trigger resources include address comparators, 
counters and sequencers. Since trace information is compressed the software debugger 
requires a static image of the code being executed. Self-modifying code can not be traced 
because of this restriction.

RealMonitor is a configurable software module, developed by ARM Inc., which enables 
real time debug. It is a lightweight debug monitor that runs in the background while users 
debug their foreground application. It communicates with the host using the DCC (Debug 
Communications Channel), which is present in the EmbeddedICE logic. The LPC2194 
contain a specific configuration of RealMonitor software programmed into the on-chip 
flash memory.