this is the first time i am using a microcontroller...a complete novice....after going thru the datasheet of at89s51 i made a programmer circuit which has:
vcc=5v
rst=5v
psen=gnd
ale\prog=connected to a bc547 collector which in turn has base n collector connected to vcc line thru 100k n 10k resistor, base line with a tactile switch
p1 and p2.0-3 = gnd thru dip switches
p0= vcc thru dip switches
ea=12v
p2.6,p2.7,p3.6,p3.7,p3.3=gnd thru dip switches....
now as per the combination given on the datasheet if i set p2.6 low and rest control signal high...i expected 2 program a byte in the given address location(p1-p2.0-3), the given data(p0 no pull up), if i press the ale tactile switch for some time....
if i keep ea=5v and all control signals low...i expected 2 read the signature bytes....
but i cant or read the signature or any byte. please help......
vcc=5v
rst=5v
psen=gnd
ale\prog=connected to a bc547 collector which in turn has base n collector connected to vcc line thru 100k n 10k resistor, base line with a tactile switch
p1 and p2.0-3 = gnd thru dip switches
p0= vcc thru dip switches
ea=12v
p2.6,p2.7,p3.6,p3.7,p3.3=gnd thru dip switches....
now as per the combination given on the datasheet if i set p2.6 low and rest control signal high...i expected 2 program a byte in the given address location(p1-p2.0-3), the given data(p0 no pull up), if i press the ale tactile switch for some time....
if i keep ea=5v and all control signals low...i expected 2 read the signature bytes....
but i cant or read the signature or any byte. please help......