Well, today is the day we actually get to use RPi.GPIO a little bit. But, before we get to that, you should know about the two different numbering systems you can use with RPi.GPIO. If you take a look at the main GPIO header (P1) of the Raspberry Pi, you’ll see that there are 26 pins. The top left. The numbers in the center (that are circled) are the Physical Pins of the Raspberry Pi. They are also called as Board Pins or Numbers. The GPIO Numbers (like Physical Pin 3 is GPIO2) are those which are seen by the Processor. This numbering is called as GPIO Numbering or BCM Numbering.
![Raspberry Raspberry](http://osoyoo.com/wp-content/uploads/2017/06/raspberry-pi-zero.jpg)
So when initially writing wiringPi, I chose to have the same default pin numbering scheme and numbered them from 0 upwards. This is no different to how the Arduino operates – “Pin 13” on the Arduino is Port B, bit 5 for example. The underlying hardware definitions are hidden by a simplified numbering scheme. On the Pi, using wiringPi, pin 0 is BCMGPIO pin 17 for example). Please for a fuller explanation and pictures.However this has subsequently been viewed as “wrong” and several people have expressed concern about my numbering scheme, however I’ve stuck with it (as by then people were using wiringPi).
And it’s proven its worth over the hardware board revisions where some pins changed their hardware definitions, however wiringPi was able to hide this from the user. As a result (for example) a program that uses wiringPi pin 2 on a Rev. 1 Pi will work unchanged on a Rev 2. Pi, however someone using BCMGPIO pin 21 on a Rev 1 Pi will need to change their program to use BCMGPIO pin 27 on a Rev 2.So wiringPi supports its own pin numbering scheme as well as the BCMGPIO pin numbering scheme, and as of Version 2, it also supports the physical hardware pin numbers (for the P1 connector only), but I would like to suggest you stick to the simplified wiringPi pin numbers. That way your programs will be portable over different hardware revisions without needing any changes.The following tables give the mapping of the Raspberry Pi GPIO Pins to the (P1) GPIO connector in relation to the pin numbers and the physical location on the connector.
This is a representation of the GPIO connector as viewed looking at the board from above. The GPIO connector is to the top-right of the board with the Ethernet and USB sockets to the bottom.Board Revisions: Please note the differences between board revisions 1 and 2 (Rv1 and Rv2 above) The Revision 2 is readily identifiable by the presence of the 2 mounting holes.The P5 connector is designed to have the header soldered on the underside of the board. Pin 1 is identified by the square solder pad. So if you solder the header on the top of the board be aware that the pin locations will be the other way round!For a printable version of these tables,Since the 26-pin GPIO connectors, a new 40-pin connector has appeared on newer Pi’s.
There is also the compute Module boards. The best way to get a description of the GPIO connector on whatever Pi you’re currently running on is to use the gpio command: $ gpio readallThis will give you a complete picture of your Pi’s GPIO connector(s) with all the numbering schemes present.
Launched about two years ago based on Broadcom BCM2837 quad core processor found in Raspberry Pi 3 board. Last year, the Raspberry Pi Foundation introduced with a slightly faster Broadcom BCM2837B0 processor, Gigabit Ethernet, and WiFi 802.11ac.So it would have made sense for the foundation to provide an upgrade to their CM3 compute modules with Broadcom BCM2837B0 processor, and that’s with the launch of Raspberry Pi Compute Module 3+ for $25 and up. Depends on your design, etc.Take a look at the block diagram for the Pi3:It should be obvious why this is no good for a cluster where you require good networking. Even worse with the CoM is that you need to supply the USB NIC yourself.If you really wanted an ARM cluster on the cheap you’d be better off picking up a bunch of Allwinner based CoMs from Aliexpress/TaoBao like this:You would only need to layout a switch and a one or two phys (to plug your access connection into) and some bulk power supply.
With the pi you’d need to do all of that and layout a USB NIC for every CoM. getting BCM2837B0 will provide better performance under some scenarios even if it is clocked at the same frequencyHmm that’s a bit confusing since performance at same clockspeed will be the same as with the older BCM2837.
It’s just throttling might be kicking in later since SoC and PCB are manufactured like everyone else around does it for years.On their announcement they wrote: ‘we have broadened the rated ambient temperature range to -20°C to 70°C’. How is that ‘broadened’ if they rated the older CM3 module for?One advantage not mentioned so far: since those VideoCore thingies have no Ethernet support and can’t run a normal OS without booting the proprietary closed source ThreadX RTOS as first stage, the exchange of the SoC now allows carrier boards to benefit from crippled USB2 attached Gigabit Ethernet if the carrier board uses Microchip’s LAN75xx chips.
At least support for LAN7515 should be present in bootloader code and ThreadX. As seen on aother device using these RPI tarts, once put in a secure closure in a industrial factory, the heat throttling ramps up and shuts down cores!“Tested ambient temperature figures with 100% processing are:20°C 4 cores 1.2GHz25°C 3 cores 1.2GHz, 1 core 1.1GHz40°C 4 cores 1GHz (or at least 1 core 1.2GHz)50°C 4 cores averaging 700MHz (or at least 1 core 1.2GHz)65°C either 4 or 1 core in 400MHz ’emergency mode’ (300MHz for longer)It is an upgrade to the market: Our first and newest member of the Revolution Pi family which is equipped with a Compute Module 3.”.
the heat throttling ramps up and shuts down cores!BS as usual. You don’t understand the stuff you spam the comments section with. Kunbus tested with loads utilizing just one or many cores and reported the throttling results at different ambient temperatures for those different scenarios. No cores were shut down, just throttling happened as expected.And what you totally missed being busy with uninformed RPi bashing: the new CM3+ we’re talking about is an improvement here due to the SoC using a heat spreader and the PCB designed to dissipate heat away from the SoC unlike earlier RPi hardware where RPi Trading folks simply ignored all thermal challenges.
I always wondered, when does it become non-viable to go with out-of-prime-time RAM like LPDDR2 compared to the sweetspot technology — LPDDR3 or LPDDR4, given how supply/demand dictate the sweetspot, and tech that falls outside the former loses the economy-of-scale advantage? Can a vendor run off stockpiles for a prolonged period of time given a popular product? LPDDR3 was dominating the market already back in H2 2014/ H1 2015. Today an OrangePI3 sans eMMC but equipped with a host of connectivity sells for $30 with 1GB of LPDDR3, and this CM is $25 with virtually nothing but 1GB of LPDDR2. That date code definitely shows recent manufacturing. I’m still going with the manufacturer running a new round of wafers through an old fab. Also note that where the wafers are manufactured can be no where close to where the chips are packaged.
When I was working at Intel we’d make wafers in CA/OR/AZ and send them off to Singapore for packaging. You send the full wafers off to the packaging factories. There they get cut into dies and tested. Then you mount the good ones in the packages and wire bond the leads.BTW, dies don’t have to be in packages.
![Raspberry pi 1 pinout Raspberry pi 1 pinout](/uploads/1/2/5/6/125617413/962567058.png)
Maybe you have run across COB PCBs like this.