Mbed Baseboard

We have moved from a test board, and produced 75 boards for teaching, the picture show's board 10, connected up and ready to test. The connections on the right hand side of the board are all the basic IO a user could want, RS232 (Grey wire), CAN (Green wire), TCPIP network (Red wire) and USB (Black wire under the MBED USB connection).

Software, including GCC port

At the moment this is a work in progress, so only the basic data is here, but for people that are interested here are the basic archives for FreeRTOS, and CMSIS, and the current state of the gcc port of the diagnostics I have

Diagnostic and test software description can be found here. this was produced by the mbed.org tool box


The all the data pins of the MBED board a connected to the outside world via a connector on the lower part of the board, giving the user access to all the MBED's I/O and 8 lines provided by an I2C expander (IC2 a PCF8574). Other devices are connected to the MBED's i/o lines converting the lines to the given bus voltage standards, and connectors on the edge of the board, these will be covered one by one later in this document.

The board also has several other devices incoperated, these are a four by four keyboard, controlled off a PCF8574 I2C i/o expander IC, a 16 charactor by 2 line LCD display, again I2C based, and four, seven segment display controlled of a SAA1064 I2C controler.

RS232 Provided by a MAX232 (ic4) driver chip and con3 a nine pin Dtype male connector mounted on the edge of the board.
Also there is a jumper (jp5) that lets the user disconnect the MAX232 device from the MBED board, so the lines can be used no the I/O expansion.
USB Host There is a USB A connector (usb-1) on the right hand side of the board for connecting USB devices to, this bus should be OK with both HID and storeage devices.
CAN The MBED can bus lines are brought to a TJA1040 can bus driver (IC3) then passed to an RJ45 connector (J1), we use an RJ45 connector to connect the board to the teaching labs green multi-drop network, the ability for bus termination is provided by a jumper (JP2).
Network An RJ45 socket (CON5) connected to the MBED network data lines, this RJ45 includes the magnetics needed for LAN connection.
SDcard The board can take micro SD cards, in this slot of upto 2G in size.
Audio In and Out Con1 (Audio in) and Con2 (Audio out) are two 3.5mm jack sockets connected to the MBES's A2D and D2A channles, No attempt has been made to level shift these lines, they are rated to take voltages up to 3.3V. Both the input and out put can be AC coupled if needed using jumpers on JP11 (In) and JP12 (Out).
I2C There is an off board connection to the I2C bus (P9/P10) via the connector marked I2Cbus, this connector gives the user +5v and Ground along with the SCL and SDA signals of the I2C bus. other jumpers are assosizted with the I2C bus, JP7 provides the ability to terminate the bus with pull up resistors, and JP13 lets the user select the keyboard address, also JP3 passes the I2C interupt signal to the CPU.
Board Overlay

I2C Device addresses
Keypad Can be 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
PIO Fixed at 0x40
SAA1064 0X70

PCC, Jan 2010