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LPC2468FBD208,551

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36P37-P39P40-P42P43-P45P46-P48P49-P51P52-P54P55-P57P58-P60P61-P63P64-P66P67-P69P70-P72P73-P75P76-P78P79-P81P82-P84P85-P85
LPC2468 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6.2 — 11 January 2013 43 of 85
NXP Semiconductors
LPC2468
Single-chip 16-bit/32-bit micro
the meantime, the flash Wake-up Timer then counts 4 MHz IRC clock cycles to make the
100 s flash start-up time. When it times out, access to the flash will be allowed. The
customers need to reconfigure the PLL and clock dividers accordingly.
7.25.4.4 Deep power-down mode
Deep power-down mode is similar to the Power-down mode, but now the on-chip
regulator that supplies power to the internal logic is also shut off. This produces the lowest
possible power consumption without removing power from the entire chip. Since the Deep
power-down mode shuts down the on-chip logic power supply, there is no register or
memory retention, and resumption of operation involves the same activities as a full chip
reset.
If power is supplied to the LPC2468 during Deep power-down mode, wake-up can be
caused by the RTC Alarm interrupt or by external Reset.
While in Deep power-down mode, external device power may be removed. In this case,
the LPC2468 will start up when external power is restored.
Essential data may be retained through Deep power-down mode (or through complete
powering off of the chip) by storing data in the Battery RAM, as long as the external power
to the VBAT pin is maintained.
7.25.4.5 Power domains
The LPC2468 provides two independent power domains that allow the bulk of the device
to have power removed while maintaining operation of the RTC and the Battery RAM.
On the LPC2468, I/O pads are powered by the 3.3 V (V
DD(3V3)
) pins, while the
V
DD(DCDC)(3V3)
pins power the on-chip DC-to-DC converter which in turn provides power to
the CPU and most of the peripherals.
Although both the I/O pad ring and the core require a 3.3 V supply, different powering
schemes can be used depending on the actual application requirements.
The first option assumes that power consumption is not a concern and the design ties the
V
DD(3V3)
and V
DD(DCDC)(3V3)
pins together. This approach requires only one 3.3 V power
supply for both pads, the CPU, and peripherals. While this solution is simple, it does not
support powering down the I/O pad ring “on the fly” while keeping the CPU and
peripherals alive.
The second option uses two power supplies; a 3.3 V supply for the I/O pads (V
DD(3V3)
) and
a dedicated 3.3 V supply for the CPU (V
DD(DCDC)(3V3)
). Having the on-chip DC-DC
converter powered independently from the I/O pad ring enables shutting down of the I/O
pad power supply “on the fly”, while the CPU and peripherals stay active.
The VBAT pin supplies power only to the RTC and the Battery RAM. These two functions
require a minimum of power to operate, which can be supplied by an external battery.
When the CPU and the rest of chip functions are stopped and power removed, the RTC
can supply an alarm output that may be used by external hardware to restore chip power
and resume operation.
LPC2468 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6.2 — 11 January 2013 44 of 85
NXP Semiconductors
LPC2468
Single-chip 16-bit/32-bit micro
7.26 System control
7.26.1 Reset
Reset has four sources on the LPC2468: the RESET pin, the Watchdog reset, power-on
reset, and the BrownOut Detection (BOD) circuit. The RESET
pin is a Schmitt trigger input
pin. Assertion of chip Reset by any source, once the operating voltage attains a usable
level, starts the Wake-up Timer (see description in Section 7.25.3 “
Wake-up timer”),
causing reset to remain asserted until the external Reset is de-asserted, the oscillator is
running, a fixed number of clocks have passed, and the flash controller has completed its
initialization.
When the internal Reset is removed, the processor begins executing at address 0, which
is initially the Reset vector mapped from the Boot Block. At that point, all of the processor
and peripheral registers have been initialized to predetermined values.
7.26.2 Brownout detection
The LPC2468 includes 2-stage monitoring of the voltage on the V
DD(DCDC)(3V3)
pins. If this
voltage falls below 2.95 V, the BOD asserts an interrupt signal to the Vectored Interrupt
Controller. This signal can be enabled for interrupt in the Interrupt Enable Register in the
VIC in order to cause a CPU interrupt; if not, software can monitor the signal by reading a
dedicated status register.
The second stage of low-voltage detection asserts Reset to inactivate the LPC2468 when
the voltage on the V
DD(DCDC)(3V3)
pins falls below 2.65 V. This Reset prevents alteration of
the flash as operation of the various elements of the chip would otherwise become
unreliable due to low voltage. The BOD circuit maintains this reset down below 1 V, at
which point the power-on reset circuitry maintains the overall Reset.
Both the 2.95 V and 2.65 V thresholds include some hysteresis. In normal operation, this
hysteresis allows the 2.95 V detection to reliably interrupt, or a regularly-executed event
loop to sense the condition.
7.26.3 Code security (Code Read Protection - CRP)
This feature of the LPC2468 allows user to enable different levels of security in the system
so that access to the on-chip flash and use of the JTAG and ISP can be restricted. When
needed, CRP is invoked by programming a specific pattern into a dedicated flash location.
IAP commands are not affected by the CRP.
There are three levels of the Code Read Protection.
CRP1 disables access to chip via the JTAG and allows partial flash update (excluding
flash sector 0) using a limited set of the ISP commands. This mode is useful when CRP is
required and flash field updates are needed but all sectors can not be erased.
CRP2 disables access to chip via the JTAG and only allows full flash erase and update
using a reduced set of the ISP commands.
Running an application with level CRP3 selected fully disables any access to chip via the
JTAG pins and the ISP. This mode effectively disables ISP override using P2[10]/EINT0
pin, too. It is up to the user’s application to provide (if needed) flash update mechanism
using IAP calls or call reinvoke ISP command to enable flash update via UART0.
LPC2468 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6.2 — 11 January 2013 45 of 85
NXP Semiconductors
LPC2468
Single-chip 16-bit/32-bit micro
7.26.4 AHB
The LPC2468 implements two AHB in order to allow the Ethernet block to operate without
interference caused by other system activity. The primary AHB, referred to as AHB1,
includes the Vectored Interrupt Controller, GPDMA controller, USB interface, and 16 kB
SRAM.
The second AHB, referred to as AHB2, includes only the Ethernet block and an
associated 16 kB SRAM. In addition, a bus bridge is provided that allows the secondary
AHB to be a bus master on AHB1, allowing expansion of Ethernet buffer space into
off-chip memory or unused space in memory residing on AHB1.
In summary, bus masters with access to AHB1 are the ARM7 itself, the USB block, the
GPDMA function, and the Ethernet block (via the bus bridge from AHB2). Bus masters
with access to AHB2 are the ARM7 and the Ethernet block.
7.26.5 External interrupt inputs
The LPC2468 includes up to 68 edge sensitive interrupt inputs combined with up to four
level sensitive external interrupt inputs as selectable pin functions. The external interrupt
inputs can optionally be used to wake up the processor from Power-down mode.
7.26.6 Memory mapping control
The memory mapping control alters the mapping of the interrupt vectors that appear at the
beginning at address 0x0000 0000. Vectors may be mapped to the bottom of the Boot
ROM, the SRAM, or external memory. This allows code running in different memory
spaces to have control of the interrupts.
7.27 Emulation and debugging
The LPC2468 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 P2[0] to P2[9]. This means that all communication, timer, and interface
peripherals residing on other pins are available during the development and debugging
phase as they are when the application is run in the embedded system itself.
7.27.1 EmbeddedICE
The 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. The EmbeddedICE protocol convertor converts the Remote Debug
Protocol commands to the JTAG data needed to access the ARM7TDMI-S core present
on the target system.
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
CAUTION
If level three Code Read Protection (CRP3) is selected, no future factory testing can be
performed on the device.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36P37-P39P40-P42P43-P45P46-P48P49-P51P52-P54P55-P57P58-P60P61-P63P64-P66P67-P69P70-P72P73-P75P76-P78P79-P81P82-P84P85-P85

LPC2468FBD208,551

Mfr. #:
Buy LPC2468FBD208,551
Manufacturer:
NXP Semiconductors
Description:
ARM Microcontrollers - MCU ARM7 512KF/USBH/ENET
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