Embedded Open Modular Architecture/EOMA-68/Tablet - Revision history

Lkcl: /* Diagram of Tablet Construction */

2012-10-06T09:32:12Z

‎Diagram of Tablet Construction

Lkcl: /* Connectors and Components */

2012-02-12T20:06:08Z

‎Connectors and Components

Lkcl: /* Connectors and Components */

2012-02-12T20:05:19Z

‎Connectors and Components

Lkcl: /* Connectors and Components */

2012-02-07T11:40:59Z

‎Connectors and Components

Lkcl: /* Connectors and Components */

2012-01-31T10:54:06Z

‎Connectors and Components

Lkcl: moved Embedded Open Modular Architecture/PCMCIA/Tablet to Embedded Open Modular Architecture/EOMA-68/Tablet: standard renamed

2012-01-14T13:07:19Z

moved Embedded Open Modular Architecture/PCMCIA/Tablet to Embedded Open Modular Architecture/EOMA-68/Tablet: standard renamed

Cschalle: Add categories

2011-10-28T07:20:48Z

Add categories

Lkcl: /* The Tablet Motherboard */

2011-09-22T00:21:55Z

‎The Tablet Motherboard

Lkcl at 00:18, 22 September 2011

2011-09-22T00:18:15Z

Lkcl: /* Connectors and Components */

2011-09-22T00:16:49Z

‎Connectors and Components

@@ Line 47: / Line 47: @@
 = Diagram of Tablet Construction =
-This diagram shows the physical construction of the tablet's components.  Critical to achieving a thin tablet, even when allowing for a 5.5mm height PCMCIA CPU Card, is to use an inline PCMCIA header as well as an inline PCI-e connector.  If one is used at all (rather than having the PCMCIA CPU card factory-installed) the PCMCIA assembly is shown being attached directly to the tablet's outer casing, rather than being attached to a PCB.  Additionally, two batteries are used (in parallel) rather than one, in order to prove a balanced weight distribution to the device.  The larger battery sizes, which could even be up to 6mm thickness, potentially allows for cheaper Lithium Polymer batteries to be used - again, reducing the overall cost of the device.
+This diagram shows the physical construction of the tablet's components.  Critical to achieving a thin tablet, even when allowing for a 5.0mm height PCMCIA CPU Card, is to use an inline PCMCIA header as well as an inline PCI-e connector.  If one is used at all (rather than having the PCMCIA CPU card factory-installed) the PCMCIA assembly is shown being attached directly to the tablet's outer casing, rather than being attached to a PCB.  Additionally, two batteries are used (in parallel) rather than one, in order to prove a balanced weight distribution to the device.  The larger battery sizes, which could even be up to 6mm thickness, potentially allows for cheaper Lithium Polymer batteries to be used - again, reducing the overall cost of the device.
 ----

@@ Line 19: / Line 19: @@
 * 12.5Mhz XTAL (for the USB Hub)
 * Power Management ICs (Buck Converters for 3.8v Lithium to 5.0v; 3.3v LDOs)
+* Step-up DC-DC Converter for the LCD Backlight [http://www.bcdsemi.com/upload/datasheet/AP3029%20D1.8%20091027.pdf AP3029]
 * An I2C EEPROM
 * An RT2070, RT8191 or Atheros ath9k USB-compliant MiniPCIe WIFI Module

@@ Line 16: / Line 16: @@
 Major components are:
 * An [http://www.st.com/internet/mcu/product/164487.jsp STM32F103RBT6] Embedded Controller (same as in the [[Embedded_Open_Modular_Architecture/PCMCIA/MicroEngineeringBoard|Micro Engineering Board]])
-* A 4-port USB-2 High-speed Hub (e.g. GL850G)
+* A 4-port USB-2 High-speed Hub (e.g. [http://elinux.org/images/e/ee/FE11-datasheet.pdf FE11]
-* 12.5Mhz XTAL (for the GL850G)
+* 12.5Mhz XTAL (for the USB Hub)
 * Power Management ICs (Buck Converters for 3.8v Lithium to 5.0v; 3.3v LDOs)
 * An I2C EEPROM
 * An RT2070, RT8191 or Atheros ath9k USB-compliant MiniPCIe WIFI Module
 * An Antenna for the WIFI Module
-* A 7in LED-backlit LCD
+* A 7in LED-backlit LCD (e.g. AT070TN93)
 * A slim-line [http://www.te.com/catalog/pn/en/1717121-1 PCMCIA Ejector Assembly]

@@ Line 20: / Line 20: @@
 * Power Management ICs (Buck Converters for 3.8v Lithium to 5.0v; 3.3v LDOs)
 * An I2C EEPROM
-* An RT2070 or RT8191 USB-compliant MiniPCIe WIFI Module
+* An RT2070, RT8191 or Atheros ath9k USB-compliant MiniPCIe WIFI Module
 * An Antenna for the WIFI Module
 * A 7in LED-backlit LCD

← Older revision		Revision as of 10:54, 31 January 2012
Line 28:		Line 28:

	The STM32F106 is chosen because of its low cost, flexibility and capabilities. The STM32F106 has 2 ADCs that can be used to monitor up to 16 simultaneous channels. Some of these channels can be used for a Resistive Touchscreen, whilst others can monitor the Battery Charge state. Also, the GPIO pins can be used for buttons, powering up of devices (e.g. for saving power, the WIFI module can be disabled) as well as doing PWM-driven Brightness Control of the LCD's Backlight. The STM32F106, costing around $1.50 to $1.70, replaces approximately $6 to $8 of discrete components and ICs, and does the exact same job, using software.		The STM32F106 is chosen because of its low cost, flexibility and capabilities. The STM32F106 has 2 ADCs that can be used to monitor up to 16 simultaneous channels. Some of these channels can be used for a Resistive Touchscreen, whilst others can monitor the Battery Charge state. Also, the GPIO pins can be used for buttons, powering up of devices (e.g. for saving power, the WIFI module can be disabled) as well as doing PWM-driven Brightness Control of the LCD's Backlight. The STM32F106, costing around $1.50 to $1.70, replaces approximately $6 to $8 of discrete components and ICs, and does the exact same job, using software.
		+
		+	For developing the formware for the STM32F, there is a GPLv3 [http://www.libopencm3.org/wiki/Main_Page STM32 Library]. Uwe Hermann describes [http://www.hermann-uwe.de/blog/libopenstm32-a-free-software-firmware-library-for-stm32-arm-cortex-m3-microcontrollers a number of Software Libre Tools] which are available that assist in the programming of STM32F devices. Also the [http://wiki.laptop.org/go/OpenEC OLPC OpenEC] Project has pre-existing firmware source code which can be ported and adapted, saving several man-months of development effort.

	The primary reason for choosing a modular USB-compliant Mini-PCIe WIFI Module is because laying out PCBs involving R.F. components is particularly tricky. Not only is it possible to simply plug in a WIFI module, but also it is possible to leverage better pricing without redesigning the product.		The primary reason for choosing a modular USB-compliant Mini-PCIe WIFI Module is because laying out PCBs involving R.F. components is particularly tricky. Not only is it possible to simply plug in a WIFI module, but also it is possible to leverage better pricing without redesigning the product.

← Older revision		Revision as of 07:20, 28 October 2011
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	[[File:Tablet_layout.png\|border]]		[[File:Tablet_layout.png\|border]]
		+
		+	[[Category:Embedded Open Modular Architecture]]
		+	[[Category:ARM processors]]

@@ Line 1: / Line 1: @@
 = The Tablet Motherboard =
-Popular by decree, but only [http://news.slashdot.org/story/11/08/20/1633239/HP-TouchPad-To-Be-Liquidated-At-Fire-Sale-Prices successfully-sold when the price is stunningly low yet the feature-set rich], tablets are the "must-have" for all ODMs and OEMs who aspire to a chunk of the large apple pie.  Key goals for this motherboard are therefore to be small, slim, low component count and based on a low-risk development strategy.  Thanks also to the modular design, the board is sufficiently simple that it may even be possible to do as a single 2-layer PCB, thus reducing costs even further.
+Popular by decree, but [http://tech.slashdot.org/story/11/08/25/2331232/Acer-CEO-Declares-a-Tablets-Bubble only successfully-sold] when the [http://news.slashdot.org/story/11/08/20/1633239/HP-TouchPad-To-Be-Liquidated-At-Fire-Sale-Prices price is stunningly low] yet the feature-set rich, tablets are the "must-have" for all ODMs and OEMs who aspire to a chunk of the large apple pie.  Key goals for this motherboard are therefore to be small, slim, low component count and based on a low-risk development strategy.  Thanks also to the modular design, the board is sufficiently simple that it may even be possible to do as a single 2-layer PCB, thus reducing costs even further.
 = Connectors and Components =

@@ Line 9: / Line 9: @@
 * PCMCIA Connector "inline" (signals conforming to [[Embedded_Open_Modular_Architecture/PCMCIA|EOMA/PCMCIA Standard]])
 * 5V Power
-* 1x PCI Express "inline" (supporting USB Wifi, not PCI-e Wifi, such as RT2070 and RT3090)
+* 1x PCI Express "inline" (supporting USB Wifi, not PCI-e Wifi, such as RT2070 and [http://www.hwtools.net/Adapter/USBMA-8191.html RT8191])
 * 1x Stereo Speakers and Microphone
 * 1x RGB/TTL LCD Output (with LED Backlight)
@@ Line 20: / Line 20: @@
 * Power Management ICs (Buck Converters for 3.8v Lithium to 5.0v; 3.3v LDOs)
 * An I2C EEPROM
-* An RT2070 or RT3090 USB-compliant MiniPCIe WIFI Module
+* An RT2070 or RT8191 USB-compliant MiniPCIe WIFI Module
 * An Antenna for the WIFI Module
 * A 7in LED-backlit LCD

@@ Line 15: / Line 15: @@
 Major components are:
-* An STM32F106RB Embedded Controller (same as in the [[Embedded_Open_Modular_Architecture/PCMCIA/MicroEngineeringBoard|Micro Engineering Board]]
+* An [http://www.st.com/internet/mcu/product/164487.jsp STM32F103RBT6] Embedded Controller (same as in the [[Embedded_Open_Modular_Architecture/PCMCIA/MicroEngineeringBoard|Micro Engineering Board]])
 * A 4-port USB-2 High-speed Hub (e.g. GL850G)
 * 12.5Mhz XTAL (for the GL850G)
@@ Line 27: / Line 27: @@
 The estimated BOM is therefore around the $30 to 35 mark, excluding the EOMA/PCMCIA-compliant CPU Card, and including the batteries, case and WIFI module.  The most expensive component is the LCD Panel, whilst the 2nd most expensive one is the batteries.
-The STM32F106 is chosen because of its low cost, flexibility and capabilities.  The STM32F106 has 2 ADCs that can be used to monitor up to 16 simultaneous channels.  Some of these channels can be used for a Resistive Touchscreen, whilst others can monitor the Battery Charge state.  Also, the GPIO pins can be used for buttons, powering up of devices (e.g. for saving power, the WIFI module can be disabled) as well as doing PWM-driven Brightness Control of the LCD's Backlight.  The STM32F106, costing around $1 to $1.50, replaces approximately $6 to $8 of discrete components and ICs, and does the exact same job, using software.
+The STM32F106 is chosen because of its low cost, flexibility and capabilities.  The STM32F106 has 2 ADCs that can be used to monitor up to 16 simultaneous channels.  Some of these channels can be used for a Resistive Touchscreen, whilst others can monitor the Battery Charge state.  Also, the GPIO pins can be used for buttons, powering up of devices (e.g. for saving power, the WIFI module can be disabled) as well as doing PWM-driven Brightness Control of the LCD's Backlight.  The STM32F106, costing around $1.50 to $1.70, replaces approximately $6 to $8 of discrete components and ICs, and does the exact same job, using software.
 The primary reason for choosing a modular USB-compliant Mini-PCIe WIFI Module is because laying out PCBs involving R.F. components is particularly tricky.  Not only is it possible to simply plug in a WIFI module, but also it is possible to leverage better pricing without redesigning the product.