Overo Design Overview

Connectors on each Overo COM

Every Gumstix Overo computer-on-module (COM) has the same three connectors and each connector has the same signal pattern.

2 x 70-pin connectors: J1 and J4

The bottom surface of each Overo COM has two (2) x 70-pin AVX 5602-series connectors: (J1) and (J4)

  • The connector labeled J1 features the LCD, PWM and analog signals.
  • The connector labeled J4 features the Extended Memory Bus and MMC signals.
  • These AVX 5602-series connectors have bosses but these connectors do not have metal tabs
  • Combined, these two 70-pin connectors allow for connection of any expansion board of the Gumstix Overo series or to a custom-designed expansion board mounted with mating 70-pin connectors.
  • Two 70-pin connectors must be installed on each custom expansion board in order to mate that custom expansion board to a Gumstix Overo COM.
  • For a low volume purchase, Gumstix sells a 10-pack of·70-pin AVX 5602-series connectors .
  • For production, customers should source these 5602-series connectors directly from·their own suppliers.
  • (Kyocera Elco part number: 245602670001829H)
  • 2D and 3D CAD drawings have been posted by Gumstix in the COMs/Overo section of pubs.gumstix.com to assist the design process of a custom enclosure or mounting assembly for an Overo-based configuration.

27-pin Connector J5

The top surface of each Overo COM has one (1) x 27-pin·Hirose FH26-27S·connector (J5):

  • The connector labeled J5 features the camera control signals.
  • For 0.3mm pitch flex circuit.
  • Gumstix sells a flex ribbon cable for connection of a Gumstix or 3rd party camera board to this 27-pin connector.

Signals

The signals and pin numbers of Connector J1, Connector J4 and Connector J5 have been detailed within this Hardware Design / Overo Series section..

The·Overo COM uses various address, signal and data lines to interface with peripherals; in general, all pins brought out to the·connectors·are available for use on expansion boards. Many signals come directly from the OMAP processor, so you can read about the function by looking at the processor data sheet.  The interconnects between the OMAP chip, peripherals on the COM and the connectors is summarized in the image below.  Full reference information is available in the Signals Document posted on this page.

gumstix_overo_signals_v1.2.jpg

Most signals available on these connectors are multiplexed so have several different functions as described in the OMAP3 Technical Reference Manual (see the PADCONF details in Section 7.4.4.3).  Currently, the pin mux-ing is established by the u-boot bootloader; it can be changed by modifying the board/overo/overo.h file in the u-boot source code and recompiling.

 

Further Design Information

General Information

The·OMAP35xx Manuals available from Texas Instruments elaborate upon the signals and can be keyed to the GPIO numbers which prefixes any signal name.

  • ·All logic is at 1.8V
  •  The·input range of the·supply voltage is approximately 3.3V – 4.2V.
  • The signals of connectors J1, J4 and J5 are connected directly to the OMAP applications processor, without buffers, with the following exceptions:
    • USB OTG signals go through the TI 65950 Power Management IC.
    • The USB Host signals go through the SMSC PHY (3326).
  • GPIO numbering is described in the GPIO prefix of any signal, including the PWM lines where a GPIO is given.
  •  PWM without GPIO is numbered according to 65950 docs. ·(PWM[0:1])
  • ADC is numbered according to 65950 docs. (ADCIN[2:7])
  • microSD and MMC
    • The microSD socket on-board each Overo COM is connected to MMC1.
    • Connectors J1 and J4 provide signals that can be used for an MMC or SD slot on an expansion board, supported by MMC3 on the OMAP. ·Check the pin-out information for connectors J1 and J4.
  • The signals named EM_Ax and EM_Dx are connected to the OMAP GPMC interface (named GPMC_Ax and GPMC_Dx in OMAP documents).
  • The microSD socket used on Overo does not have an insertion switch.
  • Gumstix supports the international specifications for USB:· OTG - 100mA and USB Host - 500mA

Overo COM Overview

To learn more about the Overo COMs, go to this Overo COM Overview section.

User Wiki

·Many hints, tips and ideas have been posted by members of the Gumstix community in the User Wiki.

Component Information

  •  To find detailed specifications and component information for any Overo COM or expansion board, review the information posted on the main page and behind each tab of each product page at www.gumstix.com for that particular Overo COM or expansion board.

Gumstix Openly Publishes the Schematic of Each Expansion Board

  • Gumstix publishes the schematic of each expansion board in the Overo series in Eagle format at pubs.gumstix.com.
  • Available under creative commons license, these schematics have been made available to enhance rapid development of a custom expansion board(s) that incorporates features and functions already designed by Gumstix Engineering.

Connecting Hardware for the Gumstix Overo Series

  • For the Overo series, Gumstix sells a pack of retaining spacers in the accessories section of www.gumstix.com.
  • While the mating of an Overo COM to an expansion board is quite secure and the board lock into place well, the addition of four retaining spacers firmly locks the two boards together for applications such as mobile, handheld and transportation.
  • An example of this enhanced board securing can be seen in these "Vibration Testing" results.

40-pin Header and 60-pin Header on Expansion Boards

  • For signal and pin number information on the 40-pin and 60-pin headers on the Overo expansion boards, go to the 40-pin Header or 60-pin Header sections.

Important Note: The 40-pin and 60-pin header information posted online in the two sections linked below should be considered accurate if there is a difference from a schematic posted at pubs.gumstix.com or any labelling on an expansion board..