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SPI Pulldown Resistors Purpose
Posted: 09 Apr 2024 12:14
by TrisM
Hi,
An educational query for myself, looking at the schematic, there are pulldown resistors on the SPI lines, but literature I have read insists that there is no requirement for pull-down/pull-up resistors on SPI lines. Only info I could find is regards mostly using pull-up for certain scenarios.
Thank you
Re: SPI Pulldown Resistors Purpose
Posted: 12 Apr 2024 21:13
by Christian_Bylund
TrisM wrote: ↑09 Apr 2024 12:14
Hi,
An educational query for myself, looking at the schematic, there are pulldown resistors on the SPI lines, but literature I have read insists that there is no requirement for pull-down/pull-up resistors on SPI lines. Only info I could find is regards mostly using pull-up for certain scenarios.
Thank you
Hello, without saying it is right or wrong.
Why pull-down or pull-up resistors? - To avoid floating pins before they are configured.
Why pull-down instead of pull-up resistors? - To avoid 5V actively high pins from the shield.
Re: SPI Pulldown Resistors Purpose
Posted: 25 Apr 2024 18:34
by Roger74
The pull down resistors given on the schematic is not what has been incorporated on the shield itself.
Interesting.
The 8101 incorporates pull up resistors on both the CS and Clock pins:
Re: SPI Pulldown Resistors Purpose
Posted: 30 Apr 2024 21:06
by TrisM
Christian_Bylund wrote: ↑12 Apr 2024 21:13
TrisM wrote: ↑09 Apr 2024 12:14
Hi,
An educational query for myself, looking at the schematic, there are pulldown resistors on the SPI lines, but literature I have read insists that there is no requirement for pull-down/pull-up resistors on SPI lines. Only info I could find is regards mostly using pull-up for certain scenarios.
Thank you
Hello, without saying it is right or wrong.
Why pull-down or pull-up resistors? - To avoid floating pins before they are configured.
Why pull-down instead of pull-up resistors? - To avoid 5V actively high pins from the shield.
Hi Christian, Thank you for the reply. Understood.