LPC2144 NXP [NXP Semiconductors], LPC2144 Datasheet - Page 24

• Manufacturer Part Number: LPC2144
• Description: Single-chip 16-bit/32-bit microcontrollers; up to 512 kB flash with ISP/IAP, USB 2.0 full-speed device, 10-bit ADC and DAC
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
LPC2141_42_44_46_48_3
Product data sheet
6.20.1 EmbeddedICE
6.20.2 Embedded trace
6.20.3 RealMonitor
6.20 Emulation and debugging
The LPC2141/42/44/46/48 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 (DCC) function built-in. The DCC
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
DCC is accessed as a co-processor 14 by the program running on the ARM7TDMI-S
core. The DCC allows the JTAG port to be used for sending and receiving data without
affecting the normal program flow. The DCC data and control registers are mapped in to
addresses in the EmbeddedICE logic.
Since the LPC2141/42/44/46/48 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 Embedded Trace Macrocell (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, which is
present in the EmbeddedICE logic. The LPC2141/42/44/46/48 contain a specific
configuration of RealMonitor software programmed into the on-chip flash memory.
Rev. 03 — 19 October 2007
LPC2141/42/44/46/48
Single-chip 16-bit/32-bit microcontrollers
© NXP B.V. 2007. All rights reserved.
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