Lpc2000

The EXTMODE and EXTPOLAR have some serious bugs for all but the latest 
LPCs. I suggest you look at the errata for the chip you are using.

Richard Duits.


bell_c_d wrote:

> I'm trying to set EXTINT0 to active-high, edge-sensitive (i.e. set
> EXTPOLAR and EXTMODE to 1), but am unable to set/read back bit 0 in
> either of the registers.  FWIW, bit 1 (for EXTINT1) sets/reads back
> successfully. 
>
> The code sample below looks correct.  Does anyone have any ideas?
>
>       byte b=EXTPOLAR;
>          E3A0320E   mov r3, #0xE0000000
>          E283397F   add r3, r3, #0x001FC000
>          E3A02F53   mov r2, #0x0000014C
>          E7D33002   ldrb r3, [r3, r2]
>          E54B300D   strb r3, [r11, #-13]
>       EXTPOLAR = 1; // set EXTINT0 active high
>          E3A0220E   mov r2, #0xE0000000
>          E282297F   add r2, r2, #0x001FC000
>          E3A01F53   mov r1, #0x0000014C
>          E3A03001   mov r3, #0x00000001
>          E7C23001   strb r3, [r2, r1]
>       b=EXTPOLAR;     
>          E3A0320E   mov r3, #0xE0000000
>          E283397F   add r3, r3, #0x001FC000
>          E3A02F53   mov r2, #0x0000014C
>          E7D33002   ldrb r3, [r3, r2]
>          E54B300D   strb r3, [r11, #-13]
>       b=EXTMODE;     
>          E3A0320E   mov r3, #0xE0000000
>          E283397F   add r3, r3, #0x001FC000
>          E3A02F52   mov r2, #0x00000148
>          E7D33002   ldrb r3, [r3, r2]
>          E54B300D   strb r3, [r11, #-13]
>       EXTMODE = 1; // set EXTINT0 edge-sensitive
>          E3A0220E   mov r2, #0xE0000000
>          E282297F   add r2, r2, #0x001FC000
>          E3A01F52   mov r1, #0x00000148
>          E3A03001   mov r3, #0x00000001
>          E7C23001   strb r3, [r2, r1]
>       b=EXTMODE;     
>          E3A0320E   mov r3, #0xE0000000
>          E283397F   add r3, r3, #0x001FC000
>          E3A02F52   mov r2, #0x00000148
>          E7D33002   ldrb r3, [r3, r2]
>          E54B300D   strb r3, [r11, #-13]
>
>
>
>
>
>
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