Having a few problems getting started, and I wondered if there were any really stupid mistakes in my circuit (schematic below).

I just want to flash an LED on port 2.0. using an adapted version of the delay code in the FAQ, like this...

;
; 1st asm51 Program!
;
; Pulses port 2 bit 0 to drive an LED I hope.
;
;
;
$MOD51
$TITLE(BYTE LED FLASH)
$PAGEWIDTH(132)
$DEBUG
$OBJECT
$NOPAGING
;
;
; Variable declarations
;
TCOUNT EQU 40H ;Address in IRAM
ALARM EQU 00H ;Bit memory
;
;
;
ORG 0000H
LJMP MAIN

ORG 000BH ;Timer 0 overflow interrupt

T0_INTERRUPT:
MOV TL0,#0B0H
MOV TH0,#03CH
DJNZ TCOUNT,T0_EXIT ;If we haven't reached 0 then jump out of int routine
CPL P2.0
SETB ALARM

T0_EXIT:
RETI
;
MAIN: MOV TMOD, 01H ;Initialise Timer 0 as 16-bit mode timer
MOV TL0,#03CH
MOV TH0,#0B0H
SETB ET0
SETB EA

LOOP: MOV TCOUNT,#20
SETB TR0
JNB ALARM,$
JMP LOOP
END





This is my first post here by the way, but I'm sure there will be many more...