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LPC2917_19_1
© NXP B.V. 2007. All rights reserved.
Preliminary data sheet
Rev. 1.01 — 15 November 2007
11 of 68
NXP Semiconductors
LPC2917/19
ARM9 microcontroller with CAN and LIN
7.1.3 IEEE 1149.1 interface pins (JTAG boundary-scan test)
The LPC2917/19 contains boundary-scan test logic according to IEEE 1149.1, also
referred to in this document as Joint Test Action Group (JTAG). The boundary-scan test
pins can be used to connect a debugger probe for the embedded ARM processor. Pin
JTAGSEL selects between boundary-scan mode and debug mode.
Table 5
shows the
boundary- scan test pins.
7.1.4 Power supply pins description
Table 6
shows the power supply pins.
7.2 Clocking strategy
7.2.1 Clock architecture
The LPC2917/19 contains several different internal clock areas. Peripherals like Timers,
SPI, UART, CAN and LIN have their own individual clock sources called Base Clocks. All
base clocks are generated by the Clock Generator Unit (CGU). They may be unrelated in
frequency and phase and can have different clock sources within the CGU.
The system clock for the CPU and AHB Multilayer Bus infrastructure has its own base
clock. This means most peripherals are clocked independently from the system clock. See
Figure 3
for an overview of the clock areas within the device.
Within each clock area there may be multiple branch clocks, which offers very flexible
control for power-management purposes. All branch clocks are outputs of the Power
Management Unit (PMU) and can be controlled independently. Branch clocks derived
from the same base clock are synchronous in frequency and phase. See
Section 8.8
for
more details of clock and power control within the device.
Table 5.
IEEE 1149.1 boundary-scan test and debug interface
Symbol
Description
JTAGSEL
TAP controller select input. LOW level selects ARM debug mode and HIGH level
selects boundary scan and flash programming; pulled up internally
TRSTN
test reset input; pulled up internally (active LOW)
TMS
test-mode select input; pulled up internally
TDI
test data input, pulled up internally
TDO
test data output
TCK
test clock input
Table 6.
Power supplies
Symbol
Description
V
DD(CORE)
digital core supply 1.8 V
V
SS(CORE)
digital core ground (digital core, ADC 1)
V
DD(IO)
I/O pins supply 3.3 V
V
SS(IO)
I/O pins ground
V
DD(OSC)
oscillator and PLL supply
V
SS(OSC)
oscillator ground
V
DD(A3V3)
ADC 3.3 V supply
V
SS(PLL)
PLL ground