LPC2157_2158 NXP Semiconductors, LPC2157_2158 Datasheet - Page 17

• Manufacturer Part Number: LPC2157_2158
• Description: The LPC2157/2158 is a multi-chip module consisting of a LPC2138/2148 single-chipmicrocontroller combined with a PCF8576D Universal LCD driver in a low-cost 100-pinpackage
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2157_2158_2
Product data sheet
6.5.1 Interrupt sources
6.6 Pin connect block
6.7 Fast general purpose parallel I/O
FIQ has the highest priority. If more than one request is assigned to FIQ, the VIC
combines the requests to produce the FIQ signal to the ARM processor. The fastest
possible FIQ latency is achieved when only one request is classified as FIQ, because then
the FIQ service routine does not need to branch into the interrupt service routine but can
run from the interrupt vector location. If more than one request is assigned to the FIQ
class, the FIQ service routine will read a word from the VIC that identifies which FIQ
source(s) is (are) requesting an interrupt.
Vectored IRQs have the middle priority. Sixteen of the interrupt requests can be assigned
to this category. Any of the interrupt requests can be assigned to any of the 16 vectored
IRQ slots, among which slot 0 has the highest priority and slot 15 has the lowest.
Non-vectored IRQs have the lowest priority.
The VIC combines the requests from all the vectored and non-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 there. If any of the vectored IRQs are pending, the VIC
provides the address of the highest-priority requesting IRQs service routine, otherwise it
provides the address of a default routine that is shared by all the non-vectored IRQs. The
default routine can read another VIC register to see what IRQs are active.
Each peripheral device has one interrupt line connected to the Vectored Interrupt
Controller, but may have several internal interrupt flags. Individual interrupt flags may also
represent more than one interrupt source.
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.
The Pin Control Module with its pin select registers defines the functionality of the
microcontroller in a given hardware environment.
After reset all pins of Port 0 and Port 1 are configured as input with the following
exceptions: If debug is enabled, the JTAG pins will assume their JTAG functionality. The
pins associated with the I
Device pins that are not connected to a specific peripheral function are controlled by the
GPIO registers. Pins may be dynamically configured as inputs or outputs. Separate
registers allow setting or clearing any number of outputs simultaneously. The value of the
output register may be read back, as well as the current state of the port pins.
LPC2157/2158 introduce accelerated GPIO functions over prior LPC2000 devices:
•
GPIO registers are relocated to the ARM local bus for the fastest possible I/O timing.
Rev. 02 — 9 February 2009
2
C0 and I
2
C1 interface are open drain.
Single-chip 16-bit/32-bit microcontrollers
LPC2157/2158
© NXP B.V. 2009. All rights reserved.
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