Here we shall explain the available hardware features on the FLOW. There are many customizations that can be done on the hardware side of the device and the best way to understand them all is to go through each one and explain it's functionality. After reading this description you should have a complete understanding of all the features of the device and it's capabilities.

Please have in mind that this description is for general public and is explained in as simple was as possible for everyone to understand. If you need a more detailed explanation then visit the Files section in the FLOW project and consult the Schematics for each FLOW component described here.

Features

The Motherboard is considered as the main component of the device and everything else available for the FLOW is connected to this PCB. The motherboard holds the following features:

1. 2 x 70pin headers for the Gumstix Overo line of platforms

2. 1 x 80pin header for the GSM, GPS or 3G modules. Other Expansions are possible

3. Sim & microSD combo Slot (the microSD is for the secondary card signals on the Overo platform)

4. 2 x 2W Stereo Speakers (with Amp) for the Overo Platform

5. 1 x 3W Mono Speaker (with Amp) for the GSM module

6. USB to Serial IC for the Overo Console Debugging

7. 1 Cell Li-Po Battery Charger

8. TEMT6000 Light Sensor

9. ADXL330 3 axis Accelerometer

10. 1W Luxeon LED for Flash or other purposes

11. 2 x Push Buttons located on the upper side of the FLOW

12. 1 x Optional 640x480 15fps TCM8230MD Camera

13. 1 x Optional 1300x1040 15fps TCM8240MD Camera

14. PIC16LF877A Microcontroller for General Use and power management of the motherboard

15. 24pin connector for connecting USB, Power adapter or other peripherals

Below is the locational map for each feature on the Motherboard, components associated with each feature are located in the same area for ease of repair or modifications:

Switches

There are several switches that can be shorted with a soldering iron for customizing the motherboard to your specific needs. Changing the path of signals from one source to the other as well as customizing the GSM module features and power management of the motherboard. These switches are as follows:

GSM Audio to Overo

By Shorting pins 3 or 2 with pin 1 you can select which input to use on the Overo platform (if any) for inputting sound directly from the GSM module to one of the Auxiliary Audio Inputs located on the Overo platform. Where 3 is Auxiliary Left and 2 is Auxiliary Right. The signals on the schematics are labeled as follows:

pin 1 -> GSM Ear +

pin 2 -> AUXRF

pin 3 -> AUXLF

The controlling pin is pin 1 and is the GSM_EAR+ signal coming from the GSM module.

Audio Amp Enable

This switch allows you to change the Enable signal on both Right and Left audio amplifiers for the Overo Audio. By shorting pin 1 with pin 2 you connect the Enable signal to VMAIN and enable the amplifiers without further control. If you connect pin 1 to pin 3 then you sonnect the Enable signal to Amp_EN which is located on the UI Microcontroller and can enable or disable the amplifiers through PORTE.1 The signals on the schematics are labeled as follows:

pin 1 -> SHDN

pin 2 -> VMAIN

pin 3 -> Amp_EN (PORTE.1 on the PIC16LF877A)

The controlling pin is pin 1 and is the SHDN signal that comes out of both amplifiers for the Overo sound.

Strobe LED

This switch allows you to change the way in which the LUXEON 1W LED operates. If pin 1 is connected to pin 2 then the LED shall operate based on the Strobe signal coming out of the TCM8240MD - 1300x1040 camera. If connected to pin 3 then this signal is controlled from the UI and is located on PORTA.2 The signals on the schematics are labeled as follows:

pin 1 -> EN

pin 2 -> Cam_Strobe

pin 3 -> Cam_str

The controlling pin is pin 1 and is the EN signal that is coming from the voltage regulator MIC5207-3.3BM5 controlling the power for the LUXEON LED.

GSM Audio Configurations & Power

In this area there are 3 types of switches. The GSM audio switches, GSM Power switch and Charging from GSM module.

Switch 1

This switch is responsible for deciding if you are going to be using the GSM features for charging your battery or to use the conventional charger located on the motherboard. By shorting this switch you connect the Power_Jack signal coming directly from the 24pin connector to the CHARGE signal on the TELIT line of modules. The signals on the schematics are labeled as follows:

pin 1 -> CHARGE

pin 2 -> Power_Jack

Switch 2

This switch is responsible for selecting to which input on the GSM module should your Microphone signal go to. The Telit line of modules has the feature of using ether the Hands Free signal set or the Hand Set signal set. For more information about these features please consult the documentation of your GSM module. The signals on the schematics are labeled as follows:

pin 1 -> GSM MIC

pin 2 -> MIC_MT+

pin 3 -> MIC_HF+

The controlling pin is pin 1 and is the GSM MIC signal coming from the microphone preamp located on the motherboard.

Switch 3

This is the EAR- switch and is responsible for selecting from which signal set should the speaker be used and is related to the Hands Free or Hand Set options available on the Telit line of modules. The signals on the schematics are labeled as follows:

pin 1 -> GSM_EAR-

pin 2 -> EAR_MT-

pin 3 -> EAR_HF-

The controlling pin is pin 1 and is the GSM_EAR- signal going to the Speaker amplifier located on the motherboard.

Switch 4

This is the Power Select switch for the GSM module and it lets you decide from which power source should the GSM module be operated. This is important in the case where you need the module to be operated regardless of the fact that the main power of the device is switched off or not or if you need to use the battery charger located on the module it self. By shorting pin 1 with pin 2 you connect the GSM power to the VBATT signal and allow the GSM module to be powered directly from the battery. If pin 1 is connected to pin 3 then the GSM module shall be powered from the VMAIN source and shall be controlled with the rest of the components. The signals on the schematics are labeled as follows:

pin 1 -> GSM Power

pin 2 -> VBATT

pin 3 -> VMAIN

The controlling pin is pin 1 and is the GSM Power signal used to power up the GSM module.

Switch 5

This switch has the same function as switch 3 but for the EAR+ signal and the pin signals are labeled accordingly.

Additional Pins

There are several additional pins that can be used directly from the motherboard, allowing it to operate in a self contained environment without the need of a battery module. Below we shall describe these pins and their functionality.

As you can see from the illustration above, there are 5 pins available and are names as follows:

pin 1 -> VBATT

pin 2 -> VMAIN

pin 3 -> GND

pin 4 -> MIC+

pin 5 -> GND

You can use these pins if you want to experiment with external power sources for the motherboard or need to have access to the microphone signal without the need of the battery module.

LED's

There are 4 LED's located on the Motherboard and they are located in the areas shown on the illustration below:

Below is a description for each LED:

LED 1 -> Main Power LED. Indicates if there is power on the VMAIN power line.

LED 2 -> GSM Module Status LED. For more information about this LED please consult the documentation of your GSM module.

LED 3 -> USB Status. Indicates if a usb connection is present or not.

LED 4 -> Battery Charge Status. When this LED is enabled then the battery is being charged. If the led is not enabled then your battery is fully charged.

The SHARP LCD module is a simple PCB from external appearance but it includes 2 Bus Transceivers for translating the 1.8v LCD signals into 3.3v signals needed for the SHARP LCD used in the SLIM Devil enclosure. There are 2 switches available on the LCD module and are shown on the illustration below:

Switch 1

This switch is responsible for selecting from which signal should the Back light of the LCD be enabled. Pin 1 (CTRL) can be connected to pin 2 which would use the UI's signal (LCD EN) or it can be connected to pin 3 and shall use the signal coming from the Overo platform (PWM1) which already has been translated to 3.3v through the bus transceiver. The signals on the schematics are labeled as follows:

pin 1 -> CTRL on the White LED driver

pin 2 -> LCD_EN on PORTC.2 of the PIC16LF877A

pin 3 -> PWM1 on the Overo platform

The controlling pin is pin 1 and is the CTRL pin located on the White LED driver for the Back Light of the LCD. This input can also read PWM signals for dimming the LCD if needed.

Switch 2

This Switch controls the LCD_INI signal for the LCD and is required for a propper initialization. It can be connected to pin 2 (3.3v) and be set HIGH as soon as the Main power source is applied or it can be connected to pin 3 (LCD_EN) and be controlled by the UI IC. The signals on the schematics are labeled as follows:

pin 1 -> LCD_INI

pin 2 -> 3.3v

pin 3 -> LCD_EN on PORTC.2 of the PIC16LF877A

The controlling pin is pin 1 and is the LCD_INI pin located on the LCD. More information about the signals located on the LCD can be found in the LCD documentation located in the Files section in the FLOW project.