Raspberry Pi 3 B+ Micro Sd Slot

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Raspberry Pi newcomers ask us to explain the difference between Raspberry Pi 4 and the older Raspberry Pi 3B+ models.

Raspberry pi 3 b+ micro sd slots

Yesterday, my Raspberry Pi 3 didn't boot, and the problem was in the micro SD slot. If I just plug power, only the red LED lights up and stays solid. But if I also press on the card, the Pi boots and all goes well. So, there was no contact with the SD card, as the cover didn't hold it good enough. Raspberry Pi Model B Specifications; Feature Pi 1 B Pi 1 B+ Pi 2 B Pi 2 B V1.2 Pi 3 B. Micro SD slot: Micro SD slot: Micro SD slot: Micro SD slot: Micro SD slot.

Obviously, Raspberry Pi 4 is one better, but you can pick up a Raspberry Pi 3 for less money (and it's more frequently found on sale). So should you buy the new Raspberry Pi 4, or pick up an older Raspberry Pi 3?

The first thing to note is that there's currently only one Raspberry Pi 4 model, but there are quite a few different Raspberry Pi 3 models. Here are some of the options:

  • Raspberry Pi 4 Model B: The fourth-generation Raspberry Pi computer

  • Raspberry Pi 3 Model B+: The final revision of the third-generation Raspberry Pi

  • Raspberry Pi 3 Model B: The third-generation Raspberry Pi

For the purposes of this article, we're looking at Raspberry Pi 4 vs Raspberry Pi 3B+ (its closest predecessor). But there are many more Raspberry Pi boards available, including the smaller Pi Zero W and energy efficient Raspberry Pi 3 Model A+. As well as older Raspberry Pi 2 Model B and the Raspberry Pi 1 Model B.

Raspberry Pi 4 vs Raspberry PI 3B+: CPU, RAM, and graphics

Raspberry Pi 4 is a clear winner when it comes to pure specifications and hardware grunt.

Raspberry Pi 4 sports a faster 1.5GHz clock speed processor (up from the 1.4GHz found on Raspberry Pi 3B+).

Raspberry Pi 3 is no slouch, though: it also features a quad-core processor and the clock-speed of 1.4GHz is in the same ballpark.

When it comes to RAM, though, Raspberry Pi 4 is streets ahead. As well as the entry-level 1GB configuration, you can get a 2GB model or 4GB model. When it comes to electronics and engineering projects, 1GB is often enough.

Raspberry Pi 3 vs Raspberry Pi 4 performance

For desktop computing, the 4GB Raspberry Pi 4 is a whole different animal to the Raspberry Pi 3B+ (see: Raspberry Pi 4 your next desktop PC in The MagPi magazine issue 85).

Raspberry

Our extensive Raspberry Pi 4 benchmark tests show a tremendous increase in performance on the new Raspberry Pi 4 over Raspberry Pi 3B+ (and all earlier models):

Raspberry Pi 4: CPU and RAM

  • Broadcom BCM2711, Quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz

  • 1GB, 2GB, or 4GB LPDDR4-3200 SDRAM (depending on model)

Raspberry Pi 3B+: CPU and RAM

  • Broadcom BCM2837B0, Quad-core Cortex-A53 (ARMv8) 64-bit SoC @ 1.4GHz

  • 1GB LPDDR2 SDRAM

Connectivity and ports

Both models of Raspberry Pi offer a range of connectivity options, including wireless LAN, Bluetooth, Ethernet, USB, and a 40-pin GPIO header (used to hook up electronic components and add specially designed Raspberry Pi HATs (Hardware Attached on Top).

Raspberry Pi 4 has a modern implementation of most of the connections. While wireless LAN is up-to-date on both models, Raspberry Pi 4 has Bluetooth 5.0 with improved speed, range, and capacity; much faster USB 3.0 ports; and unconstrained Gigabit Ethernet (which is constrained by the USB connection on the older Raspberry Pi 3).

Both devices use a microSD card slot for loading the operating system and data storage.

Raspberry Pi 4 connectivity

  • 2.4GHz and 5.0GHz IEEE 802.11ac wireless, Bluetooth 5.0, BLE

  • Gigabit Ethernet

  • 2 × USB 3.0 ports; 2 × USB 2.0 ports.

  • Raspberry Pi standard 40-pin GPIO header

  • 2-lane MIPI DSI display port

  • 2-lane MIPI CSI camera port

  • 4-pole stereo audio and composite video port

Raspberry Pi 3B+ connectivity

  • 2.4GHz and 5GHz IEEE 802.11.b/g/n/ac wireless LAN, Bluetooth 4.2, BLE

  • Gigabit Ethernet over USB 2.0 (maximum throughput 300Mbps)

  • 4 × USB 2.0 ports

  • Raspberry Pi standard 40-pin GPIO header

  • 2-lane MIPI DSI display port

  • 2-lane MIPI CSI camera port

  • 4-pole stereo audio and composite video port

Display connectivity

When it comes to display connectivity, Raspberry Pi 4 is quite literally twice as good. It sports not one but two HDMI ports, enabling you to run two display monitors. Raspberry Pi 4 is also capable of running 4K video (4096 × 2160 pixels) at 60 frames-per-second, making it ideal for modern media playback.

Raspberry Pi 3B+ has a single full-size HDMI connector, capable of running 1080p (1920×1080p).

One upside to the Raspberry Pi 3B+ is you're more likely to already have full-size HDMI cables around the house, but micro-HDMI to full-size HDMI cables are easy to source.

Raspberry Pi 4 display

  • 2 × micro-HDMI ports (up to 4kp60 supported)

  • H.265 (4kp60 decode), H.264 (1080p60 decode, 1080p30 encode)

Raspberry Pi 3 display

  • 1 × Full-size HDMI (up to 1080p)

Raspberry Pi 4 vs Raspberry Pi 3B+ power

Raspberry Pi 4 introduced a new USB-C connector for power. However, its power demands are more stringent than Raspberry Pi 3B+ (which uses an older micro-USB connector).

Both devices support the separate Power over Ethernet (PoE) HAT if you wish to power the board directly from a power-enabled Ethernet line (handy for remote networking locations).

Raspberry Pi 4 power

  • 5V DC via USB-C connector (minimum 3A*)

  • 5V DC via GPIO header (minimum 3A*)

  • Power over Ethernet (PoE) enabled (requires separate PoE HAT)

* A good-quality 2.5A power supply can be used if downstream USB peripherals consume less than 500mA in total.

Raspberry Pi 3B+ power

  • 5V/2.5A DC micro-USB connector

  • Power over Ethernet (PoE) support (requires separate PoE HAT)

Raspberry

Which Raspberry Pi should I buy?

We think both Raspberry 4 and the previous Raspberry Pi 3B+ models are great choices. You can learn about electronics and programming pretty well on both devices, although the faster processor and higher levels of RAM provided on Raspberry Pi 4 make it a much more versatile desktop computer. It also supports more demanding software, such as Scratch 3 (which only runs on the newer Raspberry Pi 4).

It makes for a much more versatile machine, too, with better internet support. And retro game emulation is much improved on the newer Raspberry Pi.

Raspberry Pi 3 B+ Micro Sd Slots

But if what you want is to play around with electronics and code, or build a low-cost media player, then Raspberry Pi 3B+ remains a good option (especially if you can pick one up at a reduced price).

The Third Pi

The Raspberry Pi 3 changes the game with its fast, 64-bit CPU and support for WiFi and Bluetooth.

The Raspberry Pi celebrated its fourth birthday on February 29, 2016, and, as befitted a leap year birthday, the Raspberry Pi Foundation surprised everyone with the release of a third-generation model of its popular nanocomputer [1]. The most important improvements for the new Raspberry Pi include a new 64-bit processor and integrated WiFi and Bluetooth. The price for the new model is unchanged at $35, but the question is whether the new model will satisfy the demands of the community. I decided to take a close look at the latest member of the Raspberry Pi family.

First Impressions

Micro

A quick glance at the Raspberry Pi 3 (RPi3) reveals a strong similarity to the RPi2 (Figure 1). The four USB ports, power supply jack, and 40-pin GPIO header are all in the usual place. The micro-USB port for power, the HDMI port, the audio and video connections, and the ports built onto the board for connecting a camera and display are all present. However, a closer look reveals some differences.

Figure 1: The Raspberry Pi 3 layout is essentially the same as its predecessor with a few minor details. Some enclosures made for an RPi2 will cover the LEDs on the RPi3.

The two LEDs, ACT and PWR, now light up next to the micro-USB port. The RUN header, which the Rasp Pi uses for rebooting, has found a new home next to the USB port. These components had to move because of the presence of the compact chip antenna. The accompanying Bluetooth/WiFi combination chip BCM43438 gives off a silvery shine on the underside of the board next to the microSD slot (Figure 2). By comparison, the chip responsible for the Xenon flash does not shine anymore. It is now coated in black, possibly because of an issue with the Xenon flash that appeared with the RPi2 [2]. Also on the underside of the RPi3, the user will see the 1GB of RAM carrying the ELPIDA label.

Figure 2: The chip responsible for the Xenon flash is now covered with a black coating.

One detail worth mentioning is the change in microSD slots. Instead of the earlier push-push microSD slot, the third generation Rasp Pi comes with a customary microSD slot that accepts an SD card without the need for a spring mechanism. This change prevents accidental ejection by mistakenly clicking on the card when inserting USB devices, which was a problem with models 2 and B+. One drawback to the new card slot is that it might be difficult to remove a card without an assist from the spring action.

The SMSC LAN9514 Hub chip separates a USB 2.0 port on the BCM2837 into four USB 2.0 ports and a 10/100Mbps network port. Thus, this well-known Rasp Pi bottleneck still exists. Even so, the WiFi and Bluetooth modules are mounted on their own ports and no longer need to share bandwidth with the remainder of the USB devices. Network boot is another interesting new feature (see the box titled 'Network Boot.')

Previous Raspberry Pi models could boot via I2C, although this function was rarely used. The new BCM2837 chip now has a modified boot ROM, which makes it possible to start a system via the network (PXE/TFTP) or a USB bulk storage device. Under the newly modified approach, the system first tries to boot via I2C, then via a microSD card or USB, until it finally searches via a DHCP query for a boot medium on the network.

The Raspberry Pi Foundation's goals with the RPi3 were to achieve compatibility, maintain pricing stability, and meet the demands of the educational market. Users will have to look elsewhere for pricey goodies like additional working memory, a SATA connection, a gigabit Ethernet port, and USB 3.0.

WiFi and Bluetooth

The Broadcom BCM43438 WiFi/Bluetooth combo kit transmits only in the 2.4GHz spectrum and provides WiFi (802.11b/g/n standard with up to 72.2Mbps net throughput), Bluetooth 4.1 (Classic as well as Low Energy), and even an FM radio receiver, which is not enabled on the Pi. (See the box titled 'No Radio.') WiFi and Bluetooth are implemented on the chip as completely independent capabilities. The only connection between the two functions concerns negotiating access to the antenna. The chip supports just a single antenna, so it doesn't support a MIMO configuration.

The Broadcom BCM43438 WiFi and Bluetooth chip has an FM radio module, but you can't activate this function on the RPi3. The antenna pin necessary for activation is in an inaccessible location on the underside of the chip. The pin is surrounded by more important pins that absolutely require connection.

MIMO (Multiple Input, Multiple Output) is a process for using multiple sending and receiving antennae for wireless communication. MIMO systems can transmit considerably more data per hertz of bandwidth used than a single antenna system.)

The WiFi adapter for the RPi3 maxes out at a gross data rate of 72.2Mbps. Measurements of the net maximum data throughput of about 40Mbps are reported on various websites. In the test for this article, I used two RPi3 systems and connected them via WiFi, with one serving as a client and the other serving as an access point. The throughput measured by using iperf was approximately 38.5Mbps. Theoretically, this data rate suffices, even for streaming 4K videos, which only require up to 16Mbps in H.265.

The microSD slot on the RPi3 now uses the second SDIO port of the SoC (Broadcom SD host). The advantage to this approach is that it offers more finely grained overclocking and thus greater SD speeds. Both SDIO ports work independently of one another, which means the entire bandwidth is available for the SD card and WiFi. To decrease the CPU load, AES encryption for the wireless network is performed on the BCM43438 in hardware.

The developers have optimized the wireless performance to the maximum legal level. Raspberry Pi creator Eben Upton was pleasantly surprised at how well the WiFi function worked, even with the Rasp Pi sitting inside of a Flirc aluminum case. The intrepid users among us who want to optimize reception further can modify a U.FL jack, which is a miniature HF plug connector, to equip the RPi3 with an external antenna. An extra antenna might not be necessary, though, because the RPi3 tested here maintained a connection to a router that was two stories above where the Rasp Pi was located.

TIP: Use the wavemon software package to monitor the quality and data throughput of the current WiFi connection.

Versions of Raspbian starting with releases from 2016-02-26 already support the WiFi adapter. To connect with wireless networks, the user merely selects the adapter from the Network menu and enters the appropriate password (Figure 3). The system stores the access data in the wpa_supplicant.conf file under /etc/wpa_supplicant/. If you prefer to work at the command line, you can use text-based tools such as wicd-curses to manage the WiFi configuration (Figure 4).

Figure 3: The graphical desktop in Raspbian comes with everything you need for setting up a WiFi connection to the router.
Figure 4: Text-based tools such as wicd-curses are an option for configuring wireless networking.

One way of localizing the settings is via the graphical desktop, starting with the Localisation tab in Preferences Raspberry Pi Configuration and then clicking the Set WiFi Country button. Alternatively, you can edit the /etc/default/crda file and modify the last line with a setting for your regulatory domain [3]. You can also perform this configuration via raspi-config. European users can use correct settings to switch to channels 12 and 13, which are forbidden in the United States.

The new WiFi function offers many interesting possibilities for use with the Internet of Things. For example, you could set up a Rasp Pi with a camera module functioning as a monitoring device with access via WiFi. Alternatively, you could outfit a Rasp Pi with sensors on the GPIO and transmit measurements via WiFi, or you could equip a Rasp Pi with a unicorn HAT that is an RGB LED matrix display, mount the computer as a clock or a lamp on the wall, and control the device via WiFi. (See the box titled 'HATS.') Another interesting idea for an application would be to connect a Rasp Pi temporarily to a network via a mobile hotspot on a smartphone for transmitting updates or measurement values.

HAT stands for Hardware Attached on Top, the designation used for add-on boards that are standardized for the Rasp Pi's 40-pin GPIO. The Rasp Pi can automatically load the drives needed for the added board on two dedicated pins reserved for an EEPROM. The EEPROM holds information about the drives that are automatically loaded via I2C.

Raspberry pi 3 b+ micro sd slot cards

Raspberry Pi 3 B+ Micro Sd Slot Machine

The BCM43438 does not support the monitor mode needed for monitoring the WiFi function, but it does have an access point mode. See the box entitled 'Access Point with Bridge-utils and Hostapd.'

Raspberry Pi 3b+ Micro Sd Slot

You can easily adapt a RPi3 connected to a router with a cable to act as an access point for connecting WiFi devices to the LAN. First, add the lines from Listing 1 to the configuration file /etc/network/interfaces, taking care to use a pound symbol # to comment out all lines relating to WiFi0, which already exists.

Install the packages hostapd and bridge-utils (Listing 2) for the access point mode. After that, create the /etc/hostapd/hostapd.conf file and populate it with the content of Listing 3. The ssid variable refers to both the name of the WiFi generated by the Rasp Pi and the wpa_passphrase, the network key you will need to modify according to personal preferences. In the interest of security, the user should modify the rights to the file so that only the root user can read the file after it has been saved:

The last step is to enter the path to the configuration file in /etc/default/hostapd:

Now restart the Rasp Pi. The access point automatically begins to operate during the boot process.

Add to /etc/network/interfaces

Access Point Packages

hostapd.conf

Raspberry Pi 3 B+ Micro Sd Slot Card

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