Post by michaelg on Feb 11, 2007 13:06:41 GMT 10
Hi there,
Im wondering if any of you electronics-savy people can help me with this problem.
I'm using a USBMOD2 module (usb interface from futurlec), it has 8 bits output - all 8 output pins are connected directly to a 74HC165N shift register.
The shift register is connected directly to a PIC16F628A microcontroller, data goes to a PORTB pin.
When i send '01010101' and read the shift registers output (not connected to the microcontroller), it reads 0v,5v,0v,5v...5v correctly.
However, when this pin is connected to the microcontroller, the high bit which is supposed to be 5v only goes to 0.8v!
So, the microcontroller reads it as a 0 instead of a 1.
Im not really that good at electronics - should i be using a resister or something somewhere?
Thanks in advance,
Michael
Im wondering if any of you electronics-savy people can help me with this problem.
I'm using a USBMOD2 module (usb interface from futurlec), it has 8 bits output - all 8 output pins are connected directly to a 74HC165N shift register.
The shift register is connected directly to a PIC16F628A microcontroller, data goes to a PORTB pin.
When i send '01010101' and read the shift registers output (not connected to the microcontroller), it reads 0v,5v,0v,5v...5v correctly.
However, when this pin is connected to the microcontroller, the high bit which is supposed to be 5v only goes to 0.8v!
So, the microcontroller reads it as a 0 instead of a 1.
Im not really that good at electronics - should i be using a resister or something somewhere?
Thanks in advance,
Michael
