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ARM i.MX Based Micro System (MX_CPU2 Board)

Universal Controller Board

The PiMX1 system is based on the FreeScale/Motorola DragonBall M9328 MX1 ARTM920T based system chip. This system has been designed for new generation of laboratory and medical instruments. The main building block of the system is CPU board. Actual CPU board revision is called MX_CPU2.

The system features:

ARM920T, 96 or 192 MHz, 16kB instruction and 16kB data cache, virtual memory management unit (VMMU) with 64+64 entry TLB
128 kB of the fast on chip embedded SRAM
32 MB 100 MHz SDRAM chip provides operation memory to the system. It is connected by 16 bit bus only to enable small board size. The penalty of 16 bit connection is not so high, because of CPU cache.
4 MB to 32 MB StrataFlash are located on MX_CPU2 board. Actual population is dependant on the expected board usage.
USB device controller
Full speed USB (12Mbit/s) device controller buffered by ISP1106DH located directly on MX_CPU1 board along with Mini-USB connector. The ISP1106DH transceiver provides software connect control. MX_CPU2 board can be directly connected to the host computer and can be even fully powered from it.
Three UARTs
UARTs of MX1 chip are accessible as 3.1 Volts levels TTL signals. The UART1 is connected to the dedicated connector directly on MX_CPU2 board and others (UART2 and UART3) are connected to IO, respective BUS extension connectors. 3.1 Volt levels can be converted to RS-232 standard in DB9 connector dongle.
ETHERNET Controller
DM9000 chip with integrated 10/100M PHY is connected to the MX1 through 16 bit data bus. The MX_CPU2 board can be populated with 10Base-T/100Base-TX transformer and four signals + LEDs connector or with integrated connector module (ICM) socket suitable for direct connection to the standard ETHERNET infrastructure.
LCD and Keyboard Connector
30-pin Molex FFC/FPC-to-Board connector is provided for LCD modules connection. The MX1 LCDC enables to directly connect most of passive and TFT LCD panels. Maximal supported resolution is 640 × 512 pixels. Up to 64k colors are supported on TFT panels and up to 16 gray levels or 4096 colors are supported for passive displays. Analog inputs for analog touch-screen decoding are provided as well. Unused pins can be used for direct matrix keyboard connection.
CMOS Video Input
20-pin Molex FFC/FPC-to-Board connector exposes CMOS Sensor Interface Module (CSI) module signals and enables direct connection of small live camera.
IO Extension Connector
50-pin PRECI-DIP Ultraminiature double row connector carries most MX1 IO signals: SecureDigital interface, UART1 and UART2, SPI and I2C interfaces signals, serial audio port (I2S), doubled analog inputs, timer, PWM and some more signals for general purpose IO functions.
BUS Extension Connector
50-pin PRECI-DIP Ultraminiature double row connector enables addition of more peripherals to the system. 16-bit data bus connected to the dedicated MX1 signals is provided as well as buffered address bus and chip-selects signals providing three 64kB regions.
I2C Bus
Two wire I2C bus enables system expansion. The SDA and SCL signals are accessible for all connected subsystems on IO Extension connector, LCD+KBD connector and CMOS Video Input connector.
JTAG Connector
10-pin header with slightly-reduced pin count JTAG interface is provided for debugging.
Boot select jumpers and LEDs
The two boot select jumpers are located on board. One select MX1 serial bootstrap mode, the second is provided for FLASH boot-block behavior selection. One LED diode can be used for software diagnostics purposes, other three are reflects ETHERNET connect and traffic state.
Power Supply
The MX_CPU2 board can be powered directly from USB +5 VDC power supply or thought dedicated pins located on IO Extension connector. Because two switching power regulators are located on board only +5 VDC or alternatively +3.1 VDC external supply is required. The board requires from 20 to 30 mA at +5 VDC for operation without power down modes if ETHERNET controller is powered down. The ETHERNET drains considerably higher power (about 100 mA). That is why DM9000 power supply can be switched off by software controllable MOSFET switch.
50 mm x 79 mm

Board has been tested successfully under ARM Linux 2.6.x ( and RTEMS 4.7 (CVS) environments. More information will follow.

PiMX1 top side
Top View of MX_CPU2 Board of PiMX1 system (Full Image)

PiMX1 solder side
Bottom View of MX_CPU2 Board of PiMX1 system (Full Image)

Components placement (top side)
Top Placement View of MX_CPU2 Board of PiMX1 system (PDF file)

Components placement (solder side)
Bottom Placement View of MX_CPU2 Board of PiMX1 system (PDF file)

Schematics diagram
Schematic Diagram of MX_CPU2 Board of PiMX1 system (PDF file)

MX_CPU2 hardware has been designed by Petr Porazil.
Work has been financed and is owned by PiKRON Ltd.
Design ideas and software work is carried by Pavel Pisa.
The published documentation can be used and copied if pointers to original sources are preserved.
There is no restriction for design use as base for derived works, but cooperation on hardware enhancements, Linux and RTEMS support would be highly appreciated.
The PiMX1 boards are now produced and used in multiple medical devices and even in one industrial terminal application.

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