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ARM LPC2294 keypad interfacing problem
Embedded Design Engineer
#1 Posted : Wednesday, May 29, 2013 10:34:55 PM(UTC)
Rank: Newbie

Joined: 5/29/2013(UTC)
Posts: 2

Dear friends
I am using ARM LPC 2294, i have interfaced LCD and keypad for keypad interfacing i have used interrupt method (because my schematic is like that so i have to write code like that only).......whenever i power on the circuit welcome message is displaying on LCD properly but when press the key of keypad it is showing nothing on LCD but after that if i RESET the micro-controller then it is again showing welcome message properly but not responding to interrupt properly.......what should i supposed to do???? .........I am sure my hardware is ok ...Is any term i am missing to activate interrupt?? plz help me......
HTML Code:
void initInterrupt()

PCB_PINSEL1 = PCB_PINSEL1 | 0x00000001; /// ///////////EINT0 = Pin P0.16////////
EXTMODE = 0x00000000; // when EXTMODE= 0 means it is level sensitive n if EXTMODE=1 then EINT0 is edge sensitive
EXTPOLAR = 0x0000000; //polarity register level or edge

VICIntSelect = (0<<14); // VICIntSelect register pin no 14 (EINT0)=0 to set IRQ register if 1 then FIQ will set
VICVectCntl0 = 0x0000002E ;
VICVectAddr0 = (unsigned)EXTINTVectoredIRQ;

VICIntEnable = VICIntEnable | 0x00004000; //Enable EINT0


Johan Dams
#2 Posted : Tuesday, June 11, 2013 2:22:06 PM(UTC)
Rank: Advanced Member

Joined: 9/16/2012(UTC)
Posts: 35


Since pressing the key seems to do something (at least, if I understand you correctly), I assume your interrupt works (no, I did not verify your code). However, without any further details, i.e., your ISR, etc. it will be very difficult for anyone to post a relevant answer.

Embedded Design Engineer
#3 Posted : Tuesday, June 11, 2013 10:14:26 PM(UTC)
Rank: Newbie

Joined: 5/29/2013(UTC)
Posts: 2

Thanks Johan Dams for your kind reply.......But now it code is working properly
Damodhar Boddukuri
#4 Posted : Thursday, September 05, 2013 2:40:43 AM(UTC)
Rank: Newbie

Joined: 9/5/2013(UTC)
Posts: 1


Whenever interfacing with keypad or buttons, we need to understand button de-bounce (i.e. whenever keypad or button is pressed and released, input to the micro controller pin toggles between HIGH & LOW for some time before settling down). This might be the root cause for your problem.

Damodhar B.
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