External Interrupt Polarity Register (Extpolar - 0Xe01F C14C) - Philips LPC214 Series User Manual

Philips Semiconductors
Volume 1
Table 11:
Bit
2
3
7:4

3.5.5 External Interrupt Polarity register (EXTPOLAR - 0xE01F C14C)

In level-sensitive mode, the bits in this register select whether the corresponding pin is
high- or low-active. In edge-sensitive mode, they select whether the pin is rising- or
falling-edge sensitive. Only pins that are selected for the EINT function (see "Pin Connect
Block" chapter on page 75) and enabled in the VICIntEnable register
"Interrupt Enable register (VICIntEnable - 0xFFFF F010)" on page
interrupts from the External Interrupt function (though of course pins selected for other
functions may cause interrupts from those functions).
Note: Software should only change a bit in this register when its interrupt is
disabled in the VICIntEnable register, and should write the corresponding 1 to the
EXTINT register before enabling (initializing) or re-enabling the interrupt, to clear
the EXTINT bit that could be set by changing the polarity.
Table 12:
Bit Symbol
0
1
2
3
7:4 -
User manual
External Interrupt Mode register (EXTMODE - address 0xE01F C148) bit
description
Symbol Value Description
1 EINT1 is edge sensitive.
EXTMODE2 0 Level-sensitivity is selected for EINT2.
1 EINT2 is edge sensitive.
EXTMODE3 0 Level-sensitivity is selected for EINT3.
1 EINT3 is edge sensitive.
- - Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
External Interrupt Polarity register (EXTPOLAR - address 0xE01F C14C) bit
description
Value Description
EXTPOLAR0 0 EINT0 is low-active or falling-edge sensitive (depending on
EXTMODE0).
1 EINT0 is high-active or rising-edge sensitive (depending on
EXTMODE0).
EXTPOLAR1 0 EINT1 is low-active or falling-edge sensitive (depending on
EXTMODE1).
1 EINT1 is high-active or rising-edge sensitive (depending on
EXTMODE1).
EXTPOLAR2 0 EINT2 is low-active or falling-edge sensitive (depending on
EXTMODE2).
1 EINT2 is high-active or rising-edge sensitive (depending on
EXTMODE2).
EXTPOLAR3 0 EINT3 is low-active or falling-edge sensitive (depending on
EXTMODE3).
1 EINT3 is high-active or rising-edge sensitive (depending on
EXTMODE3).
- Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
Rev. 01 — 15 August 2005
UM10139
Chapter 3: System Control Block
(Section 5.4.4
54) can cause
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Reset
value
0
0
NA
Reset
value
0
0
0
0
NA
24