v.s.n.kumar
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Hi,
i want to connect pull down resistor to 8051 port1 pin. because i have selected that pin as input. & i gave the output from transistor bc547 collector to that pin. but the pin is always high even the transistor is acting as closed switch or open switch. so i decided to connect the pull down resistor. but i dont know what's the value. i didn't find in data sheet. so can anybody tell. i have already connected 330 ohms. i.e one terminal of resistor to ground & other to pin. but the pin value is high. it didn't change to logic low. so plz can anybody help me.
i want to connect pull down resistor to 8051 port1 pin. because i have selected that pin as input. & i gave the output from transistor bc547 collector to that pin. but the pin is always high even the transistor is acting as closed switch or open switch. so i decided to connect the pull down resistor. but i dont know what's the value. i didn't find in data sheet. so can anybody tell. i have already connected 330 ohms. i.e one terminal of resistor to ground & other to pin. but the pin value is high. it didn't change to logic low. so plz can anybody help me.