RPI Zero 2W Board Layout: GPIO Pinout, Specs, Schematic in detail

Raspberry pi or RPI Zero 2W is the second generation Zero board released by the RPI foundation. It has a 64 bit Quad-core CPU with four A53 cores clocked at 1 GHz and a 512 Mb LPDDR2 Ram clocked at 450 MHz. It’s worth mentioning that both of these are placed in a single SIP(system in package) chip called RP3-AU or RP3. In earlier models, the RAM is placed on top of the CPU i.e, system on a chip.

Apart from this, like previous boards, this new board has a 40 pins GPIO header, mini-HDMIUSB On-The-Go ports, and a camera connector.

Raspberry pi Zero 2W
Raspberry pi Zero 2W
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New Raspberry Pi Zero 2W Specs, Board layout and Pinout

As claimed by the official RPI team, it is 5 times faster and has 40% more single-threaded performance than the original RPI zero. Raspberry pi zero and zero W is one of the most popular boards in its SOC category due to its compact size and cheap price tag.

Also, the RPI zero W was the only RPI board that has an inbuilt wireless module(WiFi and Bluetooth) and does not require any additional Hat for wireless projects. Just like RPI Zero W, the RPI Zero 2W also has an inbuilt WiFi module for wireless applications: 802.11 b/g/n Wifi and Bluetooth 4.2 along with support for Bluetooth Low Energy (BLE).

RPI Zero 2W Specs:

RPI Zero 2W Specifications
RPI Zero 2W Specifications

The detailed specification of the Zero W is given below:

SpecsDetail
ProcessorBroadcom BCM2710A1, quad-core 64-bit SoC
(Arm Cortex-A53 @ 1GHz)
Memory512MB LPDDR2
Wireless module2.4GHz IEEE 802.11b/g/n wireless LAN, Bluetooth 4.2, BLE,
onboard antenna
Connectivity• 1 × USB 2.0 interface with OTG
• HAT-compatible 40-pin I/O header footprint
• MicroSD card slot
• Mini HDMI port
• CSI-2 camera connector
Video• HDMI interface
• Composite video
Multimedia• H.264, MPEG-4 decode (1080p30)
• H.264 encode (1080p30)
• OpenGL ES 1.1, 2.0 graphics
Input power5V DC 2.5A
Operating temperature-20°C to +70°C
Form Factor65mm × 30mm

Engineers did something cool with the new RPI 2W:

Jeff Geerling from Jeffgeerling.com used an X-Ray machine to find out what’s inside the RP3 chip. To his surprise, a hidden symbol appeared under the ball grid array(BGA): Rpi’s logo!

Hidden RPI LOGO under the RP3 SIP
Hidden RPI LOGO under the RP3 SIP

**Source: JeffGeerling

RPI Zero 2W board layout:

Raspberry Pi Zero 2W Board layout
RPI Zero 2W Board layout

RP3A0-AU System in Package-

RP3A0-AU is the combination of the CPU and RAM. This is a System in package chip in which both the CPU and RAM are placed side by side. To explain what it actually means to be called a SIP, let’s take some examples.

If you look at the RPI 4 or RPI3 board layout, you will see that the RAM and processor are soldered separately to the PCB board. Both have different packages and are connected to the board like normal ICs.

Raspberry Pi 4 board design
Raspberry Pi 4 board design

Now when the RPI zero was designed, engineers wanted to make it so compact that they end up placing the RAM over the processor.

In this case, the processor(SIP) is first soldered to the PCB board and then an SDRAM is placed over this processor and soldered to the PCB while making sure the processor fits perfectly inside the SDRAM or between the legs/ball points of the SDRAM that connects it to the PCB. This arrangement is called package on package chip or POP.

Package on Package design of RPI Zero W
Package on Package design of RPI Zero W
Ram stacked over the processor in RPI Zero
Ram stacked over the processor in RPI Zero W

In this case, the design is limited by the size of the processor as finding the desired processor with a perfect size that fits under the desired RAM is very difficult.

Package on Package design of RPI Zero W(POP)
Package on Package design of RPI Zero, Zero W & 1(POP)

Hence for using a high-end processor, the hardware designers came up with a better solution for the RPI Zero 2 W: System in a Package. In SIP design, the RAM can be placed over the processor of any size because there is overall one single package that is soldered onto the PCB.

New SIP design installed in Zero 2W
New SIP design installed in Zero 2W

This solved the issue of being limited to only a particular type of processor while minimizing the form factor at the same time.

What does AU stand for in RP3A0-AU?

The AU in RP3A0-AU refers to the GOLD symbol. The reason is the use of GOLD: there are over 800 gold bond wires inside the chip(instead of copper) for a longer chip life.

Wireless module IC:

The RPI Zero 2W has a wifi module IC with 2.4 GHz 802.11 b/g/n Wifi and Bluetooth 4.2 along with support for Bluetooth Low Energy (BLE).

CSI Connector:

The CSI or Camera Serial Interface connector provides the interface between a camera and the RPI’s processor. The pi camera module can be connected to this CSI connector using a 15 pin ribbon cable for taking pictures and high definition video.

Micro USB 5V Input port 2.0:

The Micro USB port 2.0 on the right is for powering the board using a 5 V supply.

Micro USB Data port 2.0(for peripherals):

The Micro USB port 2.0 on the left is for data transfer and communication.

Mini HDMI port:

All Raspberry Pi boards have an HDMI output port that is compatible with the HDMI port of most modern TVs and computer monitors. Raspberry Pi Zero 2W has a single micro HDMI port using which you can connect it to a monitor or display.

MicroSD card slot:

The Raspberry Pi only supports cards of 32GB or smaller for data storage.

Composite Video output:

Original RPI zero has 4 additional holes and pins in front, 2 of which are for composite video. The RPI Zero 2w also supports composite video but the pads for the composite video connections are at the backside of the board.

Back side pad diagram of RPI Zero 2W
Backside pad diagram of RPI Zero 2W

40 Pin GPIO Header:

Just like the other RPI boards, Zero 2W also has the same 40 pin GPIO header configuration for interfacing the board with external devices such as sensors, actuators, and more.

RPI Zero 2W GPIO Pinout in detail

Raspberry Pi Zero 2W GPIO Pinout
Raspberry Pi Zero 2W GPIO Pinout

One powerful feature of the Raspberry Pi zero 2W board is its row of GPIO (general-purpose input/output) pins along the extreme top edge of the board. Like every Raspberry Pi chipset, Zero 2W consists of a 40-pin GPIO. The standard interface for connecting a single-board computer or microprocessor to other devices is through these General-Purpose Input/Output (GPIO) pins. GPIO pins do not have a specific function and can be customized using the software.

Raspberry PI Zero 2W Power Pins:

The board consists of two 5V pins, two 3V3 pins, and 9 ground pins (0V), which are unconfigurable.

5V: The 5v pins directly deliver the 5v supply coming from the mains adaptor. This pin can use to power up the Raspberry Pi zero, and it can also use to power up other 5v devices.

3.3V: The 3v pin is there to offer a stable 3.3v supply to power components and to test LEDs.

GND: Ground is commonly referred to as GND. GND pin is from where all voltages are measured and it also completes an electrical circuit.

Raspberry Pi Zero 2W Input/Outputs pins:

A GPIO pin that is set as an input pin, receives the incoming voltage signal sent by the device connected to this pin. A voltage between 1.8V and 3.3V will be read by the Raspberry Pi as HIGH and if the voltage is lower than 1.8V will be read as LOW.

Note: Do not give voltage more than 3.3V to GPIO pins, or else it will fry the Raspberry Pi zero.

A GPIO pin set as an output pin sends the voltage signal as high (3.3V) or low (0V). When this pin is set to HIGH, the voltage at the output is 3.3V and when set to LOW, the output voltage is 0V.

Other Important Pins on Raspberry Pi Zero 2W:

Along with the simple function of input and output pins, the GPIO pins can also perform a variety of alternative functions. Some specific pins are:

PWM (pulse-width modulation) Pins:

  • Software PWM available on all pins
  • Hardware PWM available on these pins: GPIO12, GPIO13, GPIO18, GPIO19

SPI PINS on R-Pi Zero:

SPI (Serial Peripheral Interface) is another protocol used for master-slave communication. It is used by the Raspberry pi board to quickly communicate between one or more peripheral devices. Data is synchronized using a clock (SCLK at GPIO11) from the master (RPi) and the data is sent from the Pi to our SPI device using the MOSI (Master Out Slave In) pin. If the SPI device needs to communicate back to Raspberry Pi, it sends the data back using the MISO (Master In Slave Out) pin.

  • SPI0: GPIO9 (MISO), GPIO10 (MOSI), GPIO11 (SCLK), GPIO8 (CE0), GPIO7 (CE1)
  • SPI1: GPIO19 (MISO), GPIO20 (MOSI), GPIO21 (SCLK), GPIO18 (CE0), GPIO17 (CE1), GPIO16 (CE2) 

I2C Pins on R-Pi Zero:

I2C is used by the Raspberry Pi board to communicate with devices that are compatible with Inter-Integrated Circuit (a low-speed two-wire serial communication protocol). This communication standard requires master-slave roles between both devices. I2C has two connections: SDA (Serial Data) and SCL (Serial Clock). They work by sending data to and using the SDA connection, and the speed of data transfer is controlled via the SCL pin.

  • Data: (GPIO2), Clock (GPIO3)
  • EEPROM Data: (GPIO0), EEPROM Clock (GPIO1)

UART Pins on R-Pi Zero:

Serial communication or the UART (Universal Asynchronous Receiver / Transmitter) pins provide a way to communicate between two microcontrollers or the computers. TX pin is used to transmit the serial data and RX pin is used to receive serial data coming from a different serial device.

  • TX (GPIO14)
  • RX (GPIO15)

Operating systems for RPI Zero 2W:

Board supports multiple operating systems like Kodi, Retropie, Kali Linux, and more. The RPI’s official 32-bit Raspbian operating system runs smoothly on Zero 2W. It can also support 64 bit RPI OS but may cause some poor performance.

Zero 2W Schematic:

To download the official Raspberry Pi Zero 2W Schematicclick here.

Dimensions of Zero 2W

The new Raspberry pi Zero 2W is 65mm in length and 30mm wide.

dimensions of RPI Zero 2W
Dimensions of RPI Zero 2W

Mechanical drawing

RPI Zero 2W Mechanical drawing
RPI Zero 2W Mechanical drawing

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