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Used Pins - Printable Version

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Used Pins - JAAAW - August-16th-2019

Hello,

The NetHat uses pins 24, 21, 19 & 23 for SPI0 and GPIO pins 22 & 23.

Which pin ensures the power supply? Are there any other pins that are used?

Thanks.


RE: Used Pins - Armin@netPI - August-17th-2019

The netHAT user manual you can download in the download section here https://www.netiot.com/interface/nethat/ are all pins described that are used by netHAT.

Thx
Armin


RE: Used Pins - NiechcialA - January-13th-2021

(August-17th-2019, 12:24 PM)Armin@netPI Wrote: The netHAT user manual you can download in the download section here https://www.netiot.com/interface/nethat/ are all pins described that are used by netHAT.

Thx
Armin

Hi Armin

I have a question regarding pins 27 and 28 (ID_SD, ID_SD). There are not listed as "used pins" however there are physically rooted on PCB (to the EPROM chip), and mentioned in docu but without any additional notice.

My question is: do they need to be connected to raspberry or is it OK to leve them hanging (n.c.)? Would netHAT be fully operational without them connected?

Best regards


RE: Used Pins - Armin@netPI - January-14th-2021

Well, I read the manual on page 7 describing the pinout. I see that all unused pins are described as "n.c." = not connected. All other pins like GND, 5V, SPI signals and also ID_SD,ID_SC are connected and have a function so.

Especially the ID_SD and ID_SC pins play a special role as defined by the Raspberry Pi Organization here https://github.com/raspberrypi/hats. Any HAT module have to have these two pins and an EEPROM connected to it with configuration information for the Linux Kernel. During the Pi's Kernel boot the EEPROM content is read and overlay drivers loaded in accordance to the information found or specific IO pins set to input or output mode ... all dependent on the HAT and its EEPROM. This allows to support multiple HATs with a single Kernel as the HATs "tell" the what pins they need and what are they used for.

In summary I would say that netHAT can't be operated without the two pins if you want to have SPI automatically enabled by the Kernel due to the EEPROM. But if you enable SPI manually with the "raspi-config" tool under Raspbian OS then this would probably work.

Thx
Armin