Reset Pull-Up

Other Hardware 3rd Party Boards
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spycatcher2k:
Hi all, a quick question - I've just etched a board, and was laying on the components to reflow them, and just noticed I didn't put a pull-up resistor on the reset line - I will program the chip before mounting, so its not needed for programming. The reset is hooked direct to 5v, will this be an issue?

Depends if you have a reset switch installed or not or allow access to the reset pin for external connections. If not, if should work but is not considered a good engineering practice to wire any input pin directly to +5dc. Actually the chip should work without anything wired to the reset pin as there is a 'weak' pull-up resistor to Vcc inside the chip.

Lefty

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spycatcher2k:
Cheers Lefty, Reset switch is not required, This is a one off, just to save re-etching a new board . . . . . has thought, I'll just cut the trace and 'Jury Rig' a resistor across the gap :slight_smile: .

Why don't you first just cut the trace and try out the board and if no problems then you don't need to hack in the pull-up resistor?

Lefty

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retrolefty:

spycatcher2k:
Cheers Lefty, Reset switch is not required, This is a one off, just to save re-etching a new board . . . . . has thought, I'll just cut the trace and 'Jury Rig' a resistor across the gap :slight_smile: .

Why don't you first just cut the trace and try out the board and if no problems then you don't need to hack in the pull-up resistor?

Lefty

Because the pullup is so weak, that sometimes may cause random resets to occur.