Hello Guys,
i,m trying to generate PWM for stepper motors by using AT89C5, I used TIMER2 in AUTO reload producing 1000Hz PWM frequency. Each time executing has entering into service routine, but unfortunatly i got some errors during executing the program,

i wanna to move "00" to the address of T2MOD "c9" but its not successed.

these are the instruction that coudln`t fix, if some of you ready to help.
i,m using Keil software, and AT89C52 MCU.

one problem with this istruction:
mov C9,#00H ;T2MOD address is C9

2nd one here:
mov T2CON,#01000100 ;start timer 2 producing 1kHz signal

the last problem with signature bytes;

ORG 8100
DB A5,E5,E0,A5 ;signature bytes
DB 253,255,0,0 ;id 253 = startup
DB 0,0,0,0 ;prompt code vector
DB 0,0,0,0
DB 0,0,0,0
DB 0,0,0,0
DB 0,0,0,0
DB 255,255,255,255 ;length and checksum (255=unused)
DB 'Main Controller',0
ORG 8100+64 ;executable code begins here

Hope to here from you soon.