UM10850
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User manual
Rev. 2.4 — 13 September 2016
407 of 464
NXP Semiconductors
UM10850
Chapter 29: LPC5410x Serial Wire Debug (SWD)
29.5 General description
Serial wire debug functions are integrated into each CPU, with up to four breakpoints and
two watchpoints. Boundary scan is also available.
Trace on the Cortex-M4 is supported via the Serial Wire Output.
29.6 Functional description
29.6.1 Debug limitations
Important:
Due to limitations of the CPU, the part cannot wake up in the usual manner
from Deep-sleep mode during debugging.
The debug mode changes the way in which reduced power modes work internal to the
CPU. Therefore power measurements should not be made while debugging, power
consumption is higher than during normal operation.
During a debugging session, the System Tick Timer is automatically stopped whenever
the CPU is stopped. Other peripherals are not affected.
29.6.2 Debug connections for SWD
For debugging purposes, it is useful to provide access to the ISP entry pins (see
Chapter 6 “LPC5410x Boot process”
). The ISP entry pins can be used to recover the part
from configurations which would disable the SWD port such as improper PLL
configuration, assigning another function to the SWD pins via IOCON, entry into Deep
power-down mode out of reset, etc. The ISP entry pins can be used for other functions
such as GPIO but should not be held LOW on power-up or reset.
Internal and external SWD connections are shown in
and
.