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Hello, I'm using the PSOC4 4200 microcontroller to do the power up sequence for an FPGA board. I've chosen the PSOC4 because I can get a really low pin count device. I have a question about the RESET line from the Programming Header. I've decided to use a 10 pin header (2x5) to interface with the PSOC.
Is the RESET from the header the same RESET from my push button reset?
In the graphic above this is how I think it should be wired up. The board reset line is connected to the PSOC and connected to pin 10 on the header.
Is this correct?
Thanks,
Joe
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PSoC 4 Architecture
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PSoC 4 has a reset pin, XRES, which is active LOW. XRES is internally pulled up to VDDD via a 5.6-kΩ resistor; you do not need an external pull-up resistor for XRES. You can connect a capacitor to the XRES pin, as the figure below shows, to filter out glitches and give the reset signal better noise immunity. A typical capacitance is 0.1 μF.
Also, refer to the section on Power Pin Connections on Page#6 in the Hardware Design Guide for appropriate capacitance values on VCCD, VDDA, VDDD lines.
Regards,
Dheeraj
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PSoC 4 has a reset pin, XRES, which is active LOW. XRES is internally pulled up to VDDD via a 5.6-kΩ resistor; you do not need an external pull-up resistor for XRES. You can connect a capacitor to the XRES pin, as the figure below shows, to filter out glitches and give the reset signal better noise immunity. A typical capacitance is 0.1 μF.
Also, refer to the section on Power Pin Connections on Page#6 in the Hardware Design Guide for appropriate capacitance values on VCCD, VDDA, VDDD lines.
Regards,
Dheeraj
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Dheeraj,
Hello, thank you for responding to my message. Is the XRES also connected to the programming header as show below?
I'm confused about the connection on the programming header; not sure I have it connected properly.
Thanks for helping me,
Joe
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Yes it is correct. Use the below schematic for reference:
The XRES line is directly connected to the PSoC4 MCU.
Regards,
Dheeraj
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Dheeraj,
Hello, thank you for responding to my message. I will make those changes.
Would this be a okay TVS diode:
> https://www.digikey.com/product-detail/en/on-semiconductor/SD05T1G/SD05T1GOSCT-ND/964630 >
Thanks,
Joe
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Hello Joe,
Yes, that works.
Regards,
Dheeraj
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Hello, I've updated the schematic for your comments. The Reset switch goes to the Debug Header and to the PSOC4.
How does this look?
Thank you,
Joe
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Yes, the connection to the programming header is correct now. You haven't made the previous changes I mentioned about not connecting an external pull up resistor on the line with the switch button. Just connect it directly to XRES on one side and other side to ground. It already has an internal pull up.
Regards,
Dheeraj
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Ooops, let me fix that.
Thank you
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Yes, all good now. You're welcome
Regards,
Dheeraj