He opted for a faster 64-bit ARM processor and wireless features so Raspberry Pi 3 could be a PC as well as a board for cool new devices. Other features had to be left out.
But Upton has a never-say-die attitude -- if a new technology is available at a reasonable cost, it will be added to future versions of the Raspberry Pi.
"We'll take what we can get," Upton said.
Here are five technologies that could've made the Pi 3 a better computer but didn't make the cut, due to cost, incompatibility and other issues. They could be available in the next iteration of the computer.
More RAM
The Raspberry Pi can act as an entry-level PC for Web browsing and productivity applications, but 1GB of RAM could be a bottleneck. Powerful programs can gobble up memory, and the Pi 3 won't have the resources to run many applications simultaneously. Most PCs today have a minimum of 4GB of RAM.
USB 3.0
The USB 2.0 ports in Pi 3 are out of date, and the faster USB 3.0 is in vogue. With USB 3.0, users don't have to wait long to extract files out of external storage drives. The ports, however, can be expensive, making them prohibitive for the low-cost Raspberry Pi 3. But the USB 2.0 ports are good enough to attach a mouse, keyboard and other peripherals to use Raspberry Pi 3 as a PC. The board has an HDMI port to attach monitors and a micro-SD slot for expandable storage.
New GPU
The Raspberry Pi has an aging graphics core, and a GPU upgrade would have made the computer better at gaming. The BroadCom VideoCore IV 3D graphics processor can play 1080p video at 60 frames per second, and it'll run OpenGL games. But it isn't compatible with Vulkan, a new gaming API that will bring visually stunning Linux games to PCs and mobile devices. Raspberry Pi could in the future be tempted to move over to the Vulkan-compatible ARM Mali GPU, but Broadcom has a lot invested in the CPU and GPU for the development board and so will hopefully offer Vulkan support. Upton listed graphics as a top priority when considering improvements.
ZigBee
Smart homes can be developed using Pi 3, which supports Wi-Fi b/g/n and Bluetooth technology for wireless device communications. But Pi 3 doesn't include ZigBee, a wireless technology important for home automation and IoT. ZigBee will also run on the Google-backed Thread protocol. The wireless technology could have been included in the $35 price, but Upton believes Bluetooth is the future of short-range wireless communications.
Windows 10
Raspberry Pi boards are capable of running Windows 10 IoT Core, a stripped down version of the OS for embedded devices. But now that Pi 3 is capable of being a PC, why not bring a full-bodied desktop version of Windows 10 to the board There are two problems: A full Windows 10 currently works only with x86 chips. And Windows 10 Mobile -- which can function as a desktop OS when connected to a larger screen -- runs exclusively on ARM-based chips from Qualcomm. The Pi 3 has a 64-bit ARM processor from Broadcom.