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EEPROM being destroyed during processor programming
I'm not sure of the SCLK 'stuck'. If there is hardware damage to the M25P16 clock input, then try adding a small input resistor such as 10R to the SCLK input and CE input so that you can see if the inputs are sourcing fault currents. Like you say, there must be some definite reason for only...- notaguest
- Post #48
- Forum: Circuit design
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Help cleaning up a tach pulse
> The only downside to the opto is it would require me bringing both terminals of the LED to the terminal strip I have used an on-board 3-pin jumper to allow user selection of the relevent type. The H11L1 is my preferred schmitt trigger opto, but thinking back to the logger application I...- notaguest
- Post #18
- Forum: Circuit design
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Sinusoidal phase locked loop IC: Anyone know of one
I'm not sure whether you require a variable frequency sine ouptut or the functionality of a PLL. Another option is the XR2206 to generate the sine output, and use the XR2211 to provide PLL functionality. They have both been around a long time, but are still currently manufactured.- notaguest
- Post #11
- Forum: Circuit design
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Convert Pulse Signal to 4-20mA Signal
Since the pulse is used in a totaliser function, I think you will need to use an output that will pulse slow enough to be accurately recognised by the PLC. If your maximum gas flow is 500scfm, then the 100scf pulse output will give you a pulse every 12 seconds maximum. You could then use an...- notaguest
- Post #7
- Forum: Circuit design
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EEPROM being destroyed during processor programming
Do you have passive resistor pullups on the Hold and Write protect inputs? I would also consider pullups on the chip select for that M0 chip. Are you using 3V3 for the entire board or is there also 5V powered devices associated with the serial bus? If M0 is the only one blowing, then the chip...- notaguest
- Post #46
- Forum: Circuit design
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Help cleaning up a tach pulse
Instead of a RC filter, I would use a low pass LC filter. Somthing of the order of 22uH or 47uH with a suitable capacitor to match your interference frequency. A schmitt trigger opto may also help clean up the signal and eliminate ground loops, common mode noise etc. The opto is basically a...- notaguest
- Post #16
- Forum: Circuit design
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Sinusoidal phase locked loop IC: Anyone know of one
Check out the AD5932 or similar. It's a SMT part and requires programming via a micro, but it provides an Iout sine wave that can be converted to a sine voltage via an opamp.- notaguest
- Post #10
- Forum: Circuit design
