- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
How much is the resistance of the internall pull-up of a PSoC5LP?.
Currently I have a PSoC5LP connected to 20 SPI Slave devices with 20 separate chip select lines (digital output, resistive pull up).
Since the pins are connected to Vdd, I would like to know how nuch is the current draws, and if I need an external pullup resistor
- Labels:
-
PSoC 5LP
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
GPIO pullup/pulldown resistor - min 3.5k, typ.5.6k max 8.5k
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
It is nowhere recommended to use the internal pullups for I2C. In all drawings there are always external pullups shown. Even the pioneer board uses external pullups.
Bob
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
@HL thanks
@Bob, but that for I2C not SPI, right?
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Sorry, that was for I2C only. Mis-red
Bob
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Not relevant to SPI but you can use internal pullups for I2C depending
on buss loading and speed. From NXP (Phillips) specs -
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
The spec (I2C) for those interested -
http://www.nxp.com/documents/user_manual/UM10204.pdf
Regards, Dana.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
It is convenient to use the internal resistor, but if power consumption is your concern, external resistor is the way to go, just make sure the leakage current would not change the voltage level.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Power consumption not really a problem, but space are.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
How about some 01005 resistor. (0.4mm x 0.2mm)
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
They already have a smaller one
008004 size (0.25 x 0.125 mm) !!!!!
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
that is smalllll..wonder how P&P machine handle those tiny packages.