LPC2458 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 4.1 — 15 October 2013 24 of 81
NXP Semiconductors
LPC2458
Single-chip 16-bit/32-bit micro
service routine can simply start dealing with that device. But if more than one request is
assigned to the FIQ class, the FIQ service routine can read a word from the VIC that
identifies which FIQ source(s) is (are) requesting an interrupt.
Vectored IRQs, which include all interrupt requests that are not classified as FIQs, have a
programmable interrupt priority. When more than one interrupt is assigned the same
priority and occur simultaneously, the one connected to the lowest numbered VIC channel
will be serviced first.
The VIC ORs the requests from all of the vectored IRQs to produce the IRQ signal to the
ARM processor. The IRQ service routine can start by reading a register from the VIC and
jumping to the address supplied by that register.
7.5.1 Interrupt sources
Each peripheral device has one interrupt line connected to the VIC but may have several
interrupt flags. Individual interrupt flags may also represent more than one interrupt
source.
Any pin on port 0 and port 2 (total of 64 pins) regardless of the selected function, can be
programmed to generate an interrupt on a rising edge, a falling edge, or both. Such
interrupt request coming from port 0 and/or port 2 will be combined with the EINT3
interrupt requests.
7.6 Pin connect block
The pin connect block allows selected pins of the microcontroller to have more than one
function. Configuration registers control the multiplexers to allow connection between the
pin and the on chip peripherals.
Peripherals should be connected to the appropriate pins prior to being activated and prior
to any related interrupt(s) being enabled. Activity of any enabled peripheral function that is
not mapped to a related pin should be considered undefined.
7.7 External memory controller
The LPC2458 EMC is an ARM PrimeCell MultiPort Memory Controller peripheral offering
support for asynchronous static memory devices such as RAM, ROM, and flash. In
addition, it can be used as an interface with off-chip memory-mapped devices and
peripherals. The EMC is an Advanced Microcontroller Bus Architecture (AMBA) compliant
peripheral.
7.7.1 Features
• Dynamic memory interface support including single data rate SDRAM.
• Asynchronous static memory device support including RAM, ROM, and flash, with or
without asynchronous page mode.
• Low transaction latency.
• Read and write buffers to reduce latency and to improve performance.
• 8/16 data and 20 address lines wide static memory support.
• 16 bit wide chip select SDRAM memory support.
