SARPi Project - Slackware ARM on a Raspberry Pi
Raspberry Pi Model A+ Review
The Raspberry Pi Model A+ (released in Nov 2014) is a lower-spec variant of the current RPi family, with 256MB of RAM, one USB port and no Ethernet port. The Model A+ uses microSD cards instead of full size SD cards and replaces the Raspberry Pi Model A. Due to it missing a couple of ports and an Ethernet chip, and featuring updated power-saving technology, the Model A+ consumes a reported 45% less power than the Model B or Model B+ and weighs slightly less. It does, however, feature the same 40 pin GPIO as the Model B+. It's recommended for embedded projects and projects which require very low power, and which do not require Ethernet or multiple USB ports. One thing to note is the new board size of the Model A+, because it's approximately 2cm shorter than the Model A and features four new corner-placed mounting holes. However, the Model A+ fits into a Model B+ case, it's just that the USB port is inside the case itself, rather than flush with the edge, due to the reduced size of the circuit board compared to the Model B+.
It might seem odd that the Foundation should create a computer with only one USB port and no network (Ethernet) port. However, the Model A+ still has the S5 camera connector for the camera board, and the S2 display connector for a LCD screen. So there's much you can do with the Raspberry Pi Model A. Being lighter in weight, and using less power, means the device is better suited for weather balloonists who send them up into the high atmosphere with a camera board connected to take pictures.
You are still able to run Slackware ARM Linux on the Model A+, but you'll need to connect it to a USB hub to connect multiple USB devices. If you're planning on using it on the Internet you'll need a USB wireless dongle. With only having one USB port on the Model A+ and needing to use a USB hub to add more than one device, it can get a little untidy and you need a little more space in which to set it up.
You are able to purchase a Raspberry Pi Model A+ for around US $25 / GBP ~£16 / Euro ~€22 (ex tax).
A Raspberry Pi Model A+ (top view - microSD card slot is underneath)
Raspberry Pi Model A+ Hardware Revisions
There have been a couple of revisions of the Raspberry Pi Model A+. Depending on the hardware revision of the device, these subtle distinctions can include; different manufacturer and place of origin, and different manufacturer of RAM chip.
To find out the hardware revision of your Raspberry Pi(s), use this command, as 'root' user, at the command prompt:
The currently available Raspberry Pi Model A+ revisions are:
|HW Revision||RAM||PCB Rev||Release Date||Manufacturer|
|0012||256 MB||1.1||Q4 2014||Sony (UK)|
|0015||256 MB||1.1||Q4 2014||Embest|
Raspberry Pi Model A+ Spec's
• System-on-a-chip (SoC): Broadcom BCM2835 (CPU + GPU. SDRAM is a separate chip stacked on top)
• CPU: Broadcom BCM2708 700MHz ARM11 ARM1176JZF-S core (ARMv6)
• GPU: Broadcom VideoCore IV,OpenGL ES 2.0,OpenVG 1080p30 H.264 high-profile encode/decode
• RAM: 256MB LPDDR2 SDRAM @ 400MHz
• MicroSD card socket
• Size: 65mm x 56mm x 12mm
• Weight: 23grams
• Power source: 5 V (DC) via Micro-B USB socket or GPIO header
• Power consumption: 300 mA, (1.5 W)
• HDMI socket
• 1x USB 2.0 socket (provided by the BCM2835)
• Push-push microSD card socket
• 3.5mm audio out jack and composite video connector
• Micro USB type B (power) socket
• Display and camera connectors
• 40 pin General Purpose Input/Output (GPIO) pins, Serial Peripheral Interface Bus (SPI), I²C, I²S, I2C IDC Pins, Universal asynchronous receiver/transmitter (UART)