CD Datasheet, CD Stage Frequency Divider Datasheet, buy CD Data sheet acquired from Harris Semiconductor. SCHS Page 2. Page 3. Page 4. Page 5. Page 6. Page 7. Page 8. IMPORTANT NOTICE. Texas Instruments. all relevant TOSHIBA information, including without limitation, this document, the specifications, the data sheets and application notes.

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If we combine that with some divider ics, if again I understand correctly, we could have an oscilator that will rival the expensive TCXO for a lot, lot less. After two fd4521 inverters, you see that OUT1 pin 7 is also driven Low. No, cd45221 2Hz only, to get 1Hz you need another divider. That is fairly inaccurate in the short term, but is corrected so that the long-term drift is zero, as many electric clocks use the mains frequency as a reference.


If you are lucky, any internal damage has been confined to the driver for pin 7, which you aren’t using. I looked it up on Mouser, but their datasheet is dated many years ago. I can breadboard other dividers to the circuit, etc.

I have a peculiar problem involving the CD frequency divider of which I use two in a redundant configuration as shown in my schematic snippet below: It’s gotta be one of the simplest programs you can do. Slightly clearer internal logic diagrams of the IC are available in the datasheets from: So, sure, if someone would like to post a link for a tutorial or sample generic code of their favorite one for this C language please. Note that the TI datasheet is a scan of an earlier Harris Semiconductor datasheet, so it does not have the high resolution of typical modern datasheets.

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What could be causing this? Thank you for the analysis and for taking the effort to prepare such an exhaustive answer! The logic gate just after the RESET signal is an inverter the remains of other, removed, signal lines make the inverter symbol a little unclear.

Email Required, but never shown. Hero Banned May 19, Boncuk New Member May 18, I could have used 60hz from the mains, but wanted to be independent of an external source. Heck, I could even tweak the count to adjust it’s accuracy I’ll bet. After reading a bit to understand how these things work, I was thinking I could use another I’ve edited the original image from the TI datasheet that you linked, to remove extraneous parts. The Maxim part is expensive because it is Temperature Compensated, so it has circuitry that is probably individually calibrated at several temperatures.

Could test it out with that. Thread starter jack Start date May 17, I’ve looked at that inner circuit diagram many times for various reasons, but I totally overlooked the issue with Pin 7! Most GPS receivers can give a 1 pulse per second output that is seriously accurate as it comes from the frequency standards in the satellites. Edit, if you need the code just ask. I have several pics and a programmer and am somewhat aware of it’s possibilities in this case. It may also have damaged one or both of these ICs.


However, this extra current will be less than in the case below. It depends on how much accuracy you really need. I do want one pulse per second. I have a peculiar problem involving the CD frequency divider of which I use two in a redundant configuration as shown in my schematic snippet below:. Media New media New comments Search media.

I am a fair assembly and c programmer, but very low level when it comes to circuits and components.

One Second Time Base. The reason i ask is because many times a person is looking for a one half Hertz oscillator but they ask for a 1Hz oscillator. Can I use the 3 volt type in a five volt circuit?

One Second Time Base | Electronics Forum (Circuits, Projects and Microcontrollers)

Therefore you are effectively trying to cause a short-circuit at pin 7 of the IC, limited mainly by the IC’s output driver current capability. How do I know I am getting the newest, improved version of the ?

A well adjusted watch crystal is accurate enough for most applications. Since the logic Low driven on pin 7 is not exactly zero volts, there will be an extra unplanned current from pin 7 to Gnd. Then i have to ask, why the problem? Cheap, easy, and accurate. To participate you need to register.