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4

Look at the MCP23017/MCP23S17 datasheet. As you rightly say the SPI protocol does not use those address bits, it uses chip select to address the device. However the command set used by the device does use the address bits. The SPI control byte for the MCP23S17 uses those bits to select the device. That allows you to have multiple MCP23S17 with one chip ...


4

SMTP, or Simple Mail Transport Protocol is the mail delivery mechanism in use currently on the Internet. You can't send email without using SMTP in one way or another, either directly, or via a script or program that accesses a tool (for example an API or email-based website) that ties directly with SMTP on its back end.


3

Check out this test of RPi performance w.r.t various network interfaces. Built-in WiFi on an RPi 3 is capped at 36 Mbps, and a USB dongle is capped at about 80Mbps in ideal conditions. At 10 meters distance, those numbers drop to 32 and 64 Mbps respectively. After you factor in overhead from two interfaces running simultaneously, routing performance losses, ...


3

It is simple to control a small fan with the Pi GPIO. I use a simple transistor circuit (with only 3 inexpensive components). I use the Pi 5V pin to power my fan, but this could be used with an external 12V supply for 12V fans. This is suitable for fans which draw up to 500mA. Substitution of a power transistor could be used to power larger fans. ...


2

i've had a further look at it. My RP3's SD card had popped and split in half. Turns out i'm not the only one. There's a lot of people online that have had the same issue as me. They take it down after months, turn it on. And within a minute its unbareable to touch


2

If you only want to change the static ip address on an interface you can just do it with ip address in two steps, for example: rpi ~$ sudo ip address del 192.168.0.1/24 dev eth0 rpi ~$ sudo ip address add 192.168.0.2/24 dev eth0 ip address has also options change and replace but these will not modify the ip address, but only the flags of an existing ip ...


2

Pro and cons of Raspberry pi 3B+ vs Raspberry pi 4 depends on what you want to do. You don't specify it. So for a beginner to just start learning with Raspberry Pi I suggest to use a Raspberry Pi 4B. It is the latest version and has important improvements about Raspberry Pi 3B+, mainly real 1GB ethernet, USB 3.0, larger amounts of RAM up to 4 GByte, boot ...


2

For GPIO 2/3 (pins 3/5) to operate as the I2C bus they must be in a GPIO mode called ALT0. They are set to this mode when the Linux I2C/SMBus driver is loaded. The RPi.GPIO module is changing the mode of GPIO 2/3 to INPUT. This stops the proper operation of the I2C bus. You need to again set the mode to ALT0 for GPIO 2/3 for the bus to operate again. As ...


2

The mode of each pin is either in, out or any of the other functions (I2C in this case). Pins 3 and 5 are in ALT0 mode by default after reboot if the I2C driver is active. Type gpio readall on the command line to see which pins are in which mode. To do the same as gpio mode 8 alt0 gpio mode 9 alt0 in code, you need to do something like GPIO.setup(3, ...


1

The easiest would be to use 1 RPi for every screen to ensure scalability, and wired network connections between the nodes to avoid delays and dropouts. Configurations with multiple displays per node will be substantially more tricky to set up and operate. I think the cheapest configuration would be 4 x RPi Zero ($5 a piece) with USB network adapters (less ...


1

You don't say what OS or list any code, but do tag ssmtp which is deprecated in Buster and hasn't been updated in years. There are replacements. I use msmtp (although not Python). See https://raspberrypi.stackexchange.com/a/100704/8697


1

I have the same problem using branch v2 of this RPIO fork (https://github.com/JamesGKent/RPIO/tree/v2) on a Pi Zero W. RPIO builds successfully and the error occurs already when importing PWM from RPIO. Solution: Include sys/sysmacros.h in file source/c_pwm/mailbox.c was missing.


1

So, it turns out I did not have enough power and I was using a lot of the pins. I also may have accidentally damaged something as well. I have decided to get a refund (which was successful) and just buy a new one from canakit. I will try to be more careful. Usually, Amazon is good with returns.


1

There is a chance that some connections in your rpi is shorted somehow. It seems your board is not working again so I am leaving some suggestions for others. Always clean your raspberry pi with a brush. The main problem of unused raspberry pi is they have dust on them and conductor particles can easily burn everything if not cleaned properly.


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