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PCF8574 I2c port extender current sink always sinking proble
Hi, I built a circuit using a PCF8574 I²c IO port extender to drive a transistor to switch relays. I used a current sinking scheme. So, output 1 = off, output 0 = on. The problem...
Tuesday, 13 November 2012 - 19:41
Low tolerance digital variable resistors
Hi, I'm designing a circuit (24 dB/octave Linkwitz/Riley audio crossover) that calls for 16 adjustable resistors and they have to match within 1% of each other, or maybe 2%. I'm...
Saturday, 10 November 2012 - 18:04
Atmega168 behaves very buggy after uploading code
Hi, I have a weird problem with an Atmega168. I was adding some features to my software when all of a sudden, the controller started behaving very buggy; the update_display()...
Monday, 6 February 2012 - 21:00
PCF8574 i2c port extender: maximum current quesiton
Hi, I'm having some trouble with my PCF8574 I²c port extender chip, possibly related to output current. I've successfully implemented 3 other of these chips, but this is the only...
Monday, 19 September 2011 - 11:01
SPI never signals SPIF after writing to SPDR
I'm trying to send SPI commands to a PGA2311 audio chip with an atmega168, but writing to the SPDR never yields a 1 in SPIF in SPSR (status register). The atmega168 is the...
Tuesday, 6 September 2011 - 14:50