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Philips Semiconductors
Volume 1
Table 10:
Bit
0
1
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 73) 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 11:
Bit Symbol
0
1
2
User manual
External Interrupt Mode register (EXTMODE - address 0xE01F C148) bit
description
Symbol
Value
Description
EXTMODE0 0
Level-sensitivity is selected for EINT0.
1
EINT0 is edge sensitive.
EXTMODE1 0
Level-sensitivity is selected for EINT1.
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).
Rev. 01 — 24 June 2005
UM10120
Chapter 3: System Control Block
(Section 5.4.4
52) can cause
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Reset
value
0
0
0
0
NA
Reset
value
0
0
0
23
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