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Serial interrupt driven issues--timer1/2

Dai Ma

Hi,
I have a 24 byte tx buffer. When i send the buffer from a uM to pc in a polled manner, timer 2 works fine with the following setting:

mov SCON, #01010000b
mov RCAP2L, #0DCh
mov RCAP2H, #0FFh
mov T2CON, #00110100b

but if i try to use serial interrupt (to receive some chars and do some other calculations) then the send is hanged after the 1st char....
my send codes are (with 30h as the beginning of the tx buffer):

Send:
mov R0, #30h
Main:
clr TI
mov SBUF, @R0
Wait: jnb TI, Wait
inc R0
cjne R0,#48h, Main

However, if the baudrate was set by using timer 1 then the code will work fine....timer 1 setting:

mov TMOD,#20h
mov PCON,#80h
mov TH1,#250
mov TCON,#40h
mov SCON,#50h

what was wrong??
pls help, thanks!!

I use a 11.0592 xtal set to generate a baud of 9600. My code which works with timer1 is (but not when timer2 was used):

.equ TxNow, 01h

.equ StackBase,50h


.ORG 0
ajmp Init


.ORG 23h
ajmp SerInt


;[]------------------------[]
;| Interrupt Routines |
;[]------------------------[]

SerInt:
push PSW
push ACC
push 00h
jbc TI,SerOut
jbc RI,SerRx


SerRx:
mov P0,SBUF

SerOut:
pop 00h
pop ACC
pop PSW
reti



CheckRdy:
mov A,P0
cjne A,#'U',cTxNow
setb TxNow
mov P0,#0h
ret
cTxNow:
clr TxNow
ret


;[]------------------------[]
;| Setup |
;[]------------------------[]

Init:

mov TMOD,#20h
mov PCON,#80h
mov TH1,#250
mov TCON,#40h
mov SCON,#50h
setb ES
setb EA


;[]------------------------[]
;| Main Program |
;[]------------------------[]

mov 30h, #'H'
mov 31h, #'e'
mov 32h, #'l'
mov 33h, #'l'
mov 34h, #'o'
mov 35h, #'!'
mov 36h, #' '
mov 37h, #'T'
mov 38h, #'x'
mov 39h, #'R'
mov 3Ah, #'x'
mov 3Bh, #' '
mov 3Ch, #'s'
mov 3Dh, #'u'
mov 3Eh, #'c'
mov 3Fh, #'c'
mov 40h, #'e'
mov 41h, #'s'
mov 42h, #'s'
mov 43h, #'!'
mov 44h, #' '
mov 45h, #':'
mov 46h, #')'
mov 47h, #' '
Main1:
lcall CheckRdy
jnb TxNow, Main1
jbc TxNow, Send

Send:
mov R0, #30h
Main:
clr TI
mov SBUF, @R0
Wait: jnb TI, Wait
inc R0
cjne R0,#48h, Main
clr TxNow
ajmp Main1

.END

When timer2 was used, it would just hang after sending 'H'.....