THE LATEST ITERATION of CSR's famous Bluetooth chip, the Bluecore 7, manages to squeeze four radio functions into a single 3.2mm by 3.6 mm core. The chip, plus its associated eight external components, should only consume 30mm².

The four functions which Bluecore 7 provides include both the standard and low-energy version of Bluetooth, FM radio (both receive and transmit) along with Enhanced GPS (E-GPS).

The INQ reckons that support for E-GPS is almost certainly the most significant addition. CSR's John Halksworth claimed that adding support for it into a handset could cost as little as $1 (above the cost of the Bluecore itself).

What that means is that a GPS capability could be added into mid-tier handsets which would be great news for network operators who wish to push location based services (LBS).

CSR maintains that E-GPS is much better than Assisted GPS (A-GPS) because it takes advantage of both a data link and cellular triangulation. In theory this means your position gets stored so LBS can work inside a building.

The greatest challenge with this 4-in-1 comes from providing support for FM. Some handset vendors cheat by using the handsfree cable as an FM antenna. To enable designers to put an internal FM antenna inside the casing, CSR provides a high maximum output power of +4.5 dBm.

The requirement for FM transmit came from the handset vendors, Halksworth claims. Given that consumers are storing all their MP3s on the handset, they want to be able to listen to them via the car radio. This even became legal in the UK recently, too.

Bluetooth low energy used to be called Ultra Low Power Bluetooth which itself is based on Wibree. It's basically a very simple implementation of Bluetooth which enables the handset to talk to embedded sensors powered by button batteries.

Curiously CSR has no current plans to make the radio chips for such sensors.

The INQ asked Halksworth why Wi-fi isn't integrated into a Bluecore chip. The simple answer was that both Bluetooth and Wi-fi operate at the same frequency so it's difficult to get them work that close together.

There was also a hint that the extra engineering work involved to solve such a problem wouldn't provide a meaningful payback given that it's much simpler just to use two different chips.

He was more hopeful of adding in support for NFC (Near Field Communication) because that operates at 13.56 MHz not 2.4 GHz like Bluetooth and Wi-fi.

That could turn a handset into an Oyster payment card which would be extremely useful for London commuters.

Bluecore 7 silicon is available already and should ship in Q4 2008 with the first products using it appearing in Q1 2009. CSR currently supplies a base unit for testing that boasts a separate ROM so that bug fixes can be downloaded and tried before the final design goes to the fab. µ