Tag Archives: electronics

Some thoughts about the Raspberry Pi compute module

CM_and_pi-small-500x375 The Raspberry Pi foundation has announced the “Raspberry Pi compute module”. As we are big fans of the Raspberry Pi, this looks like an interesting product to us. However, let’s have a closer look first.

The product is clever for the Raspberry Pi foundation. Many of the Raspberry Pis sold already are not used by private persons, but in industrial applications. The good availability and the low price of the Raspberry Pi made it a nice platform for these many applications. With the new board, the foundation clearly targets this market.

The compute module basically consists of the Broadcom SoC chip and a 4GB flash. The 4GB flash is really nice, because you don’t need an SD card with this module. All other hardware that is included in the Raspberry Pi Model B is missing. The most critical: there is no ethernet controller. Using a standard SO-DIMM module is good for large producers, but for small quantities this increased costs again. Also there is no voltage regulator on the board, which means you need external 3.3V and 1.8V voltage regulators. Therefore solutions based on this board won’t be cheaper, but most likely more expensive than solutions based on the Raspberry Pi.

Some people where already dreaming about clusters of compute nodes for computing applications. I don’t think this is a good idea. If you’re really looking for CPU performance, the Raspberry Pi is not the first choice. There are many other ARM based SoCs available, that provide much better performance and are only a bit more expensive.

Powering a Raspberry Pi from 12-18V


Our next project will use an external 12-18V power supply. It will be again a Raspberry Pi powered device. Having an additional 5V/1A power supply in addition to the main 18V power supply is not really a nice solution. Therefore we want to create this 5V power supply from the 18V supply. As the Raspberry draws 500-1000mA current, a simple linear regulator is not an option. It has to be a switching regulator. The LMR12010 from Texas Instruments (formerly National Semiconductors)  seems to be an interesting chip. It does not need many external components, but still has an acceptable efficiency. There are chips with better efficiency, however these usually need external switches.  Today we tested the chip using the Evaluation kit from TI. Interestingly, the Eval kit still has the National Semiconductor logo on it.  The result looks promising. The efficiency is good enough, no additional heat sinks or cooling for the switching regulator is needed.

Check out this 20V-powered Raspberry Pi:


HiFiBerry Digi pre-order started

hifiberrydigiOur new digital output board for the Raspberry Pi – the HiFiBerry Digi. can be pre-ordered now for our a special introductory price. We expect to ship the first units about mid of February.

The HiFiBerry Digi adds an optical and a fully isolated electrical output to your Raspberry Pi. Samples rates up to 192kHz/24bit are supported on both outputs.

Linux driver development has been finished already, production samples were tested. Everything works very well.

Pre-order it now!

HiFiBerry Digi support in Raspberry Pi Linux kernel

hbdigi-proto-raspberryOur HiFiBerry Digi will be available soon. Now, another major step in development has been finished: The HiFiBerry Digi support is included in the official Raspberry Pi Linux 3.10 kernel. If you’re interested in the source code, check out the pull request on Github.

I want to thank Florian Meier – the author of the Raspberry Pi I2S kernel module – for his great support. During the last weeks, I learned a lot about GIT and Linux kernel patches.

Build your Squeezebox client with piCorePlayer

Steen Pedersen has updated his piCorePlayer to support our HiFiBerry DAC. piCorePlayer is a Squeezebox client based on a minimal Linux system. It boots from the SD card, but runs completely in the RAM after booting. It also supports WiFi dongles. We tested it with the small Raspberry Pi Model A, that has only a single USB port and used a small LogiLink USB WiFi adapter – it worked very well.


We can recommend piCorePlayer for all Squeezebox fans!