Fujitsu Develops Windows 7-based Handset Using 2 Processors

May 30, 2011
Tomohisa Takei, Nikkei Electronics
The F-07C is an i-mode-compatible mobile phone that can be used as a Windows 7-based PC.
The F-07C is an i-mode-compatible mobile phone that can be used as a Windows 7-based PC.
[ If it clicks, the expanded picture will open ]
Like normal mobile phones, it supports i-mode-related services such as "i-Mode Mail" as well as "Osaifu Keitai" (mobile wallet).
Like normal mobile phones, it supports i-mode-related services such as "i-Mode Mail" as well as "Osaifu Keitai" (mobile wallet).
[ If it clicks, the expanded picture will open ]
Fujitsu will release a cradle equipped with UBS host ports and an HDMI output port.
Fujitsu will release a cradle equipped with UBS host ports and an HDMI output port.
[ If it clicks, the expanded picture will open ]
The handset stores a lithium-ion rechargeable battery (3.7V, 1,400mAh). It continuously operates in the Windows 7 Mode for about two hours per charge.
The handset stores a lithium-ion rechargeable battery (3.7V, 1,400mAh). It continuously operates in the Windows 7 Mode for about two hours per charge.
[ If it clicks, the expanded picture will open ]

Fujitsu Ltd had a press conference on its "F-07C" mobile phone, which can be used as a Windows 7-based PC, May 26, 2011.

It functions in two modes: "Mobile Mode," in which the F-07C can be used as a mobile phone that supports NTT Docomo Inc's i-mode mobile service, and "Windows 7 Mode," in which it can be used as a Windows-based PC. The two modes were realized by using two microprocessors.

The F-07C, which Fujitsu describes as the world's smallest personal computer, was announced by NTT Docomo as one of the mobile phones designed for the summer of 2011 and is scheduled to be released in June or July 2011.

"Because the mobile phone can be used as a PC, it can serve users for much longer hours," said Kuniaki Saito, personal business director of Fujitsu.

Equipped with Atom, OMAP

To make the F-07C operate as a Windows-based PC, Fujitsu equipped the handset with Intel Corp's "Intel Atom processor Z6xx Series" microprocessor (maximum operating frequency: 1.2GHz) and "SM35 Express" input-output circuit.

"We combined the processor of the Moorestown (a chipset for smartphones) and the input-output circuit of the Oak Trail (a chipset for tablet PCs)," Fujitsu said. "We used our own combination to have an input-output interface of normal PCs while reducing power consumption."

To reduce power consumption in the Windows 7 Mode to 1.5W, the company limited the maximum operating frequency of the Atom processor to 600MHz.

To make the F-07C operate as an i-mode-compatible mobile phone, Fujitsu equipped it with Texas Instruments Inc's "OMAP" microprocessor. Like the other i-mode-compatible mobile phones developed by Fujitsu, the F-07C runs Symbian OS-based software platform on the OMAP. It is possible to switch between the two systems running on the two different processors just by pressing a button located on a side of the mobile phone.

"It might be better to integrate them into one processor," Fujitsu said. "But at this point, we need the two-processor structure so that we do not have to reduce the number of functions of the phone as an i-mode compatible handset and a Windows-based PC."

Input interface managed on mobile phone side

(Continue to the next page)

Input interface managed on mobile phone side

To realize the structure in which different systems run on two microprocessors, both of the microprocessors have main memory. Also, Fujitsu ensured that peripheral devices can basically be accessed by only one system so that two systems do not compete with each other. It seems that the system on the OMAP (Symbian) manages peripheral devices except for those that can only be used in the Windows 7 Mode (such as wireless LAN, HDMI and USB host Note 1)).

Note 1) Fujitsu developed a "cradle set," which will be separately sold, for the F-07C. It can be used as a charging stand and has four UBS ports and an HDMI output port. The F-07C does not have any HDMI output port or USB host port.

For example, even in the Windows 7 Mode, user inputs via the touch panel, keypad, etc are detected by Symbian on the OMAP side and sent to Windows 7. Incoming calls to the mobile phone are also managed by Symbian. When the F-07C receives a call, it automatically switches the Windows 7 Mode to the Mobile Mode.

Data can be exchanged between the two systems by sharing an SD memory card.

"As the integration of the two systems proceeds, they become more complicated," said Nobuo Otani, executive director of Fujitsu. "We limited the integration to data sharing. And, as a result, we succeeded in developing clear-cut systems."