3.6.1. FPGA configuration

At power-up the FPGA loads its configuration data from configuration flash memory.

The image loaded into the FPGA is determined by the image select switch S1 on the baseboard (see Figure 3.1 for the location of S1).

The image selection options are listed in Table 3.1.

Table 3.1. FPGA image selection

S1-1FPGA image
OFFFPGA image 1 (this is the image supplied with the board)
ONFPGA image 2 (this area is available for future use)


The configuration flash can hold two FPGA images however, only one FPGA image is provided.

The configuration flash is a separate device and not part of the user NOR flash.

You can use the appropriate Progcards utility connected via a JTAG debugger or the USB Config port to reprogram the PLDs, FPGA, and flash if the PB-A8 is placed in configuration mode. See The progcards utilities.


You are advised not to program these devices with any images other than those provided by ARM.


The 1.5V cell battery provides the VBATT backup voltage to the external DS1338 time-of-year clock. The battery is expected to last for approximately 10 years from manufacture of the PB-A8.

To replace the battery:

  1. Power on the PB-A8. If the battery is removed while the board is powered down, the time-of-year data will be lost.

  2. Remove the old battery.

  3. Insert the new battery. Ensure that the positive terminal is facing upwards in the holder.

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