Introducing the XJDemo v4.2 Board

Circuit Description

The circuit block diagram is shown above. Click one of the green devices to read its datasheet. The circuit schematic is also available in PDF format.

There are two JTAG-enabled devices on the XJDemo v4 board. U1 is an Intel Max V CPLD (5M40Z-E64C5N) and U2 is a NXP Kinetis microcontroller (MK22FN128VDC10).

There are also eleven other ICs on the board that do not have JTAG capability (non-JTAG devices). These are:

Device Ref.	Part number	Description
U3	W25Q80DVUXIE	8 Mbit SPI flash memory, accessible from both the CPLD and the MCU.
U8	74LVC125A	Tri-stateable buffer, used to allow the CPLD to access the SPI flash.
U6	IS61WV25616EDBLL	Static (256k × 16) RAM with its address, data and control signals connected to the MCU.
U11	NCD9830DBR2G	ADC which uses an I2C interface connected to the CPLD and the P1 connector.
U5	AT24C02D	EEPROM which uses an I2C interface, on the same I2C bus as the ADC.
U12	LIS2HH12TR	Accelerometer which uses an I2C interface connected to the MCU.
U4 and U7	ISL3172EIUZ	Half-duplex RS485 transceivers connected to the CPLD.
U9	74LVC2G02GS	Quadruple 2-input NOR gate device.
U10	74LVC1G04	Single inverter.
U15	4AVC9112	Fan-out buffer used for the 8 MHz clock signals.

The Fault Creation Jumpers (designated FCJ1 on the board) will be used to simulate various faults on the PCB. The default connections that are needed for the board to operate correctly are shown below, and also marked on the silk screen of the board next to the jumpers.

In detail, the connections are as follows:

• FCJ1.3 to FCJ1.4 – this links the two halves of net COMMS_INT.
• FCJ1.11 to FCJ1.12 – this links the two halves of net SDA for the EEPROM.
• FCJ1.15 to FCJ1.16 – this links the two halves of net IO18.
• FCJ1.19 to FCJ1.20 – this links the two halves of net A8.
• P2.1 to P2.2 – this is part of the RS485 loopback.
• P2.3 to P2.4 – this is part of the RS485 loopback.
• JP1.1 to JP1.2 – this connects the nTRST pin of the MCU (U2) to the XJLink.

There are also two spare jumpers fitted (labelled Spare Jumpers) under the FCJ1 jumpers. These will be used to simulate faults during this tutorial.