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Hi, I am using an SD card controlled by a microcontroller. The SD card will allow a user to input a program for a controller system. The user interface is an 8x10 inch plate with an embedded keypad along with a slot where the user can inset an SD card. Behind the plate would be an SD card...
Hi, I am using an ISD17xx sound record/playback chip in SPI mode (using a microcontroller). I am looking for a method for downloading .wav files from my PC computer to the ISD device. I have connected a cable between my sound card and Pin9 (Aud IN) of the sound chip and can successfully...
After hacking on this for awhile this afternoon, I finally got the circuit working. It seems that the bus clock on the uP was too fast. Thanks for your suggestions.
Hi, I am using the MAX7219 to control a LED display. However, I can't seem to get it to light any of the digits. To start, I would like to go into test mode to light all digits. The wiring seems to be correct. Also, the MAX7219 just seems to stay in shutdown mode (all digits high, segments...
Thanks for the input Karesz. The varistors are: V22ZA1P. From the datasheet:
Varistor Voltage at 1mA DC test current: Vnom=18.7; Vnom_max=26
Maximum Clamping Voltage: Vc:43, Ipk=2.5
The voltage at the varistor can be anywhere from 12V to 15V, so I'm not sure what the actual ohmic value is...
After "exercising" the circuit a bit more, here is the situation. BTW. I am using a Freescale HCS08 microcontroller, which can souce 10mA. I don't believe driving the ULN2003 should be a problem.
When I give "TIP32-1-BASE" a logic high from the uP, I do get 12V at the Q4 collector. However...
Hi,
I have "cut-and-paste" a working circuit to save some time. Please see the attachment for details. The circuit seems to be designed to use the ULN2003 to drive several TIP32 PNP transistors, which in turn drive several relays. The pins named "uP Pin" are connected to various I/O pins on...
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