1.2 Headers, Connectors, Jumpers
The MCPF1412M06 evaluation board includes several jumpers and test points that allow users to modify the board’s functionality. These include:
- J3: This jumper selects the termination voltage source for the I2C bus. In the “VCC” position, the I2C bus is terminated using the on-board 5V regulator and on-board resistors (R4 and R5). In the "Ext." position, an external voltage source—applied at the "External Bus" test points (TP5 and TP6)—is used for termination, still utilizing the on-board resistors. If on-board termination resistors are not required, they may be removed, provided that appropriate termination is available elsewhere on the I2C bus.
- J6: This jumper configures the termination for the SYNC pin on the MCPF1412M06. If the SYNC function is not in use, the jumper should remain in the "GND" position. Setting the jumper to "VCC" pulls the SYNC pin to VCC through a 4.99 kΩ resistor (R9), suitable for driving the SYNC pin with an open-collector or open-drain output. Removing the jumper allows the SYNC pin to float, in which case it must be driven externally. Test points TP15 and TP16 are provided for this purpose.
- J8: This jumper allows selection of one of three preconfigured output voltages: 1.2V, 1.0V, or 850 mV. The selected position connects the appropriate biasing resistor to a voltage divider, which is then connected to the FB pin of the MCPF1412M06. Removing the jumper disconnects the voltage divider biasing resistor, resulting in the FB pin being connected to the output voltage through a resistance. In this configuration, the output voltage can be adjusted directly using PMBus commands or register values.
- J9: This jumper is used to select the offset applied to the base I2C and PMBus addresses for communication. By default this jumper is in the “0” position, resulting in an I2C address of 0x08 and a PMBus address of 0x70. Offsets up to 0xF (15 decimal) can be selected by changing the jumper position. The base addresses are stored in register 0x21 (I2C_BASE for I2C and PMBUS_BASE for PMBus, allowing for full address space configuration.