Embedded Open Modular Architecture/EOMA-26

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EOMA-26 Specification

This page describes the specification of EOMA-26. The number of pins on the interface is 26; the physical form-factor is the 34x75x5mm ExpressCard format.

Re-purposing of the ExpressCard interface and form-factor has been chosen to create portable mass-volume (100 million units and above) ultra-low-cost Embedded Computing Modules (Computer on Module).

The interfaces are:

  • 3-channel LVDS (covering up to approximately 1280x800 @ 18-bit colour)
  • I2C
  • USB (Low Speed, Full Speed, and optionally Hi Speed/480 Mbit/s)
  • RS232 UART (Tx and Rx only)
  • 4-pin SD/MMC (which must automatically support 2-pin, 1-pin and SPI mode)
  • 2 dedicated pins of General-purpose Digital I/O (GPIO) with a mandatory 5 further multiplexed GPIO (covering UART and SD/MMC)

These interfaces are NOT OPTIONAL for CPU Cards. All CPU Cards MUST provide all interfaces. I/O Boards on the other hand are free to implement whichever interfaces are required for the device. The only exception is I2C (due to the EOMA-68 identification EEPROM), which MUST be provided by all I/O Boards

Exactly like ExpressCard Cards, EOMA-26 CPU Cards may have absolutely any functions, any additional connectors, peripherals and so on without limitation, except for compliance with the EOMA-26 pinouts and physical size constraints. These additional functions, which may include access ports in the casework, may extend outwards from the user-facing end of the CPU Card to any practical extent, exactly as with ExpressCard.

Target Market for EOMA-26

The target market for EOMA-68 is smaller or lower-cost devices than EOMA-68. Tablets and Laptops up to 11in in size in particular would ideally make use of EOMA-26. In essence, the EOMA-26 form-factor was designed to take advantage of the decreasing cost and increasingly-high specification of lower-end SoCs such as the A10S, AM3359 [1] and so on.

Table of EOMA-26 pinouts

Row 1 Row 2
* 1 GROUND * 14 RIN 0- Negative LVDS differential data output
* 2 USB2 (Data-) * 15 RIN 1+ Positive LVDS differential data output
* 3 USB2 (Data+) * 16 RIN 1- Negative LVDS differential data output
* 4 PWR (5.0V) * 17 RIN 2+ Positive LVDS differential data output
* 5 GPIO2 / UART_TX * 18 RIN 2- Negative LVDS differential data output
* 6 GPIO3 / UART_RX * 19 PWR (5.0V)
* 7 I2C Clock (SCL) * 20 SDC-CMD
* 8 I2C Data (SDA) * 21 SDC-CLK
* 9 GPIO0 * 22 GPIO4 / SDC-3
* 10 GPIO1 * 23 GPIO5 / SDC-2
* 11 CLKIN+ Positive LVDS differential clock output * 24 GPIO6 / SDC-1
* 12 CLKIN- Negative LVDS differential clock output * 25 SDC-0
* 13 RIN 0+ Positive LVDS differential data output * 26 GND