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PDA development kit gets SD slot

Sep 15, 2009 — by LinuxDevices Staff — from the LinuxDevices Archive — 6 views

Toradex is now sampling a revised design kit targeting creation of customer-specific PDAs. The “Limestone” kit, version 2.0, features an 806MHz Marvell PXA320 processor, a “rich” board-to-board extension interface, plus an optional battery, case, and cover, the company says.

Toradex says its Limestone PDA development kit, version 2.0, is an outgrowth of the company's SODIMM-sized, Marvell-based "Colibri" computer modules, such as the Colibri PXA320, Colibri PXA290, and Colibri PXA270.

Like the first Limestone kit, released in November of last year, however, the Limestone doesn't employ the actual SODIMM modules. Instead, its 806MHz PXA320 processor and other features are integrated onto the main board pictured later in this story.

Version 2.0 of the Limestone board is said to offer the SD card slot that was optional on the first version. Toradex also notes that the revised board is smaller (115 x 67mm), employs just a single board-to-board connector with ring shielding, is available with an optional RF shielding box, and no longer includes a vibration motor.

As before, the board includes the Marvell CPU, 128MB of RAM, 1GB of flash storage, a touchscreen connector, audio, USB host/client ports, and battery charging/monitoring. The top of the board, pictured below, includes a microphone connector, plus a 140-pin Hirose connector that carries signals to and from the optional touchscreen and custom extension boards. The underside of the board (not pictured), meanwhile, includes an on/off switch, a 5VDC power input, a USB host/client connector, a battery connector, and the SD card slot.

Toradex's Limestone PCB (top)
(Click to enlarge)

Signals relayed via the Hirose connector include the following, according to Toradex:

  • Keypad
  • Audio I/O (both digital and analog)
  • Camera interface
  • SD/MMC (second socket)
  • USB host
  • USB host/client (shared)
  • 3 x UART
  • SPI
  • 12C
  • GPIOs
  • Reset in/out
  • Power supply

A block diagram of Toradex's Limestone, version 2.0
(Click to enlarge)

Features and specifications listed by Toradex for the Limestone, version 2.0 include:

  • Processor — Marvell PXA320 clocked at 806MHz
  • Memory — 128MB of RAM and 1GB of flash
  • Display (optional) — 3.5-inch display (touchscreen or non-touchscreen) with 320 x 240 resolution
  • I/O:
    • USB host/client connector
    • Power input
    • Display/expansion board connector, relaying the signals detailed earlier
  • Expansion — SD slot
  • Battery type — Can handle "almost any" single-cell lithium-ion or lithium-polymer battery
  • Operating range — 0 to 70 deg. C
  • Dimensions (optional housing) — 4.72 x 2.75 x 0.98 inches (120 x 70 x 25mm)


The Limestone, version 2.0 is sampling now, priced at 159 Euros (approximately $232) for the baseboard, and 60 Euros (about $108) for a battery. According to Toradex, the Limestone ships with Windows CE 5.0, yet is also compatible with Linux or Android via "third-party support." The Android support is said to be enabled by Noser Engineering.

In 2007, Toradex launched a Colibri Dev's Corner community site said to offer news, patches, forums, and wikis aimed at helping build a collaborative Linux development community around its Colibri boards. The site is still running, with several patches and kernel beta releases available, but the last wiki entry was posted almost a year ago.

More information on the Limestone 2.0 kit may be found on the company's website, here.

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