I have use following code for 8051 by NXP(p89v51rd2)
#include<reg51.h> #define p2 P2 sfr P1=0x90; sbit led1=p2^0; sbit s=P1^0; void main() { s=1; while(1) { if(s==0) { led1=1; } else { led1=0; } } }
I have connected led on port 2 (pin no. 0) circuit of sensor is here elecrom.wordpress.com/.../
this sensor on black background generate 0 to 1.5 Volt
when i connect ground to port 1 via 1k led glow but when i give output from sensor (IR sensor) output volt of sensor increase to 5V. Is there something wrong with program?
when i connect ground to port 1 via 1k led glow but when i give output from sensor (IR sensor) output volt of sensor increase to 5V.
I am trying to overcome a problem understanding you.
do you mean that when you have the sensor alone, the output is 0 to 1.5 V, but when you connect it to a port pin the output is 5V?
on that assumption my first thoughts would be
I do not recall if the p89v51rd2 port pins are configurable, if so, you have configured an input pin as push-pull. If the port pin is quasi-bidirectional and the sensor output rises when you connect to a pin, the sensor is open collector output.
Erik
yes when I have the sensor alone, the output is 0 to 1.5 V, but when you connect it to a port pin the output is 5V
what is solution?
get the datasheet fot the sensor, it is 99.9% likely open collector output, in which case what you see is what you should expect.