3.3.3 Swapping the SPI Flash Memory Devices

The EV42J24A development board comes with four 3.3V Quad SPI memory devices installed in the flash memory sockets. Some customer may wish to use specific SPI flash devices from other memory vendors or to install 1.8V devices. If a decision is made to not use the default memory devices, it is the responsibility of the customer to ensure compatibility.

3.3V SPI Flash Devices

To upgrade to a different vendor but still maintain 3.3V operation, power down the board, remove the existing SPI Flash devices and replace them with the new memory devices. Follow the procedures defined in the previous sections for powering up the board and programming the flash devices with the DediProg programmer.

1.8V SPI Flash Devices

To configure the board to run with 1.8V SPI flash devices, some jumper positions must be modified. Prior to making these modifications, power down the board by removing all power to it. There are three jumpers that need to be modified to change the board configuration from the default mode of using 3.3V flash chips to using 1.8V chips. Jumpers J10 and J12 can be changed by moving the jumper cap. J14 is a trace-link jumper and will need to be cut.
Figure 3-9. Jumper Settings for 1.8V SPI

The CEC1736 supports two SPI banks of up to two chips each. Each bank can support either 1.8V or 3.3V SPI chips. J10 and J12 are used to select the voltage for each channel, with VTR1 supporting SPI channel 0 and VTR2 supporting SPI channel 1. The CEC1736 is a flow-through data path; therefore, the supporting application processor interface must also supply the correct voltage signals for the selected SPI. For the EV42J24A, the support application processor is the MEC1723, and its supply voltage is controlled by the trace link jumper J14. The default for this jumper is set to 3.3V. To convert to 1.8V, cut the trace link and install a 0603 zero Ohm resistor in position 2-3 at J14.

After modifying the desired jumper settings, follow the procedures defined in the previous sections for powering up the board and programming the flash devices with the DediProg programmer.