Tiny SODIMM-style COM runs Linux on Atmel Cortex-A5 SoC
May 27, 2015 — by Eric Brown 1,459 viewsKa-Ro’s SODIMM-style “TXA5” COM runs Linux on Atmel’s SAMA5D42 SoC, offers Ethernet, LCD, USB, GPIO, and serial I/O, and supports industrial temperatures.
The TXA5 is the first Atmel-based member of the Ka-Ro Electronics family of “TX” COMs. Most of Ka-Ro’s COMs have used Freescale processors, and many have been sold under the Strategic Test label, including the i.MX283-based TX-28S from 2012.
Like all these modules, the TXA5 comes with an open source Linux BSP, and uses the company’s 200-pin, SODIMM-style TX computer-on-module standard, which comes in two sizes: 68 x 36mm, or 68 x 26mm. In the TXA5’s case, the smaller format applies.
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The TXA5 carries a promise of 10-year availability, and supports the extended temperature ranges of -25 to 85°C or -40 to 85°C. It’s designed for “cost-sensitive industrial applications as well as devices requiring low-power or battery operation,” says Ka-Ro.


TXA5 front and back views
(click images to enlarge)
The module is built around the SAMA5D42 variant of Atmel’s single-core, Cortex-A5 SAMA5D4 SoC. The SoC supports 32-bit DDR3 in addition to 16-bit, but lacks the 720p video decoder of the ATSAMA5D43 or ATSAMA5D44. Like its siblings, the SoC offers security features including ARM TrustZone and on-the-fly encryption and decryption.

Atmel SAMA5D4 SoC block diagram
(click image to enlarge)
The TXA5 is outfitted with 256MB of 32-bit DDR2 RAM, 128MB NAND flash, and 4GB eMMC flash. The module offers “all standard TX interfaces,” including 10/100 Ethernet, USB 2.0 host and OTG ports, and an LCD TFT display interface.
The COM is further equipped with a parallel camera interface, up to 103 GPIOs, plus I2C, SPI, I2S, SD, 2-wire, UART, and PWM.
Specifications listed for the TXA5 module include:
- Processor — Atmel SAMA5D42 (1x Cortex-A5 core @ 528MHz)
- Memory:
- 256MB 32-bit DDR2 RAM
- 128MB NAND flash
- 4GB eMMC
- Networking — 10/100 Ethernet controller
- Other I/O (via 200-pin TX edge connector with 3.3V I/O power):
- LCD TFT (24bpp) with 4x overlays
- 2-wire 400Kbps, I2C
- USB 2.0 host
- USB 2.0 OTG
- 2x I2S synchronous serial audio
- 3x UART
- SPI, I2C, PWM
- Parallel CMOS image sensor (ITU-R BT. 601/656)
- 2x SD 2.0 and eMMC 4.3
- Up to 103 GPIOs
- Other features — 10 year availability
- Power — 5V; PMIC
- Operating temperature — -25 to 85°C or -40 to 85°C
- Dimensions — 68 x 26 x 4mm
- Operating system — Linux 4.1 with UBoot
TX Mainboard 7
The TXA5 ships with an open source Linux BSP with sources ported to the TXA5 module’s specific interfaces and released to mainline Linux, says Ka-Ro Electronics. A Debian 6.0 VMware virtual machine is available to customize uBoot, the Linux 4.1 kernel, and root filesystem.

TX Mainboard 7
(click image to enlarge)
The module can be plugged into the latest version of the standard carrier board shared by all TX COMs: the TX Mainboard 7. This 148 x 100mm development board ships with complete schematics and BOM, as well as a power supply and interface cables.
The TX Mainboard 7 is available in headless or display versions, with the latter supporting TFT LCD displays or dual LVDS displays. The display version is available with a 5.7-inch, 640 x 480-pixelcapacitive touchscreen with backlight.
The baseboard supports most of the COM’s listed I/O, except for the camera interface. Additional features include multiple RS485 and RS232 ports, CAN and SATA ports, an SD slot, a 3.5mm audio jack, and a JTAG interface (see block diagram, farther above).
Further information
The Ka-Ro TXA5 COM and development kits are available now. The price for a single module starts at $84, and quantity pricing is available on request from Ka-Ro Electronics distributors. More information may be found on the TXA5 product page.
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