SMART Embedded Computing MVME2502, Installation And User Manual

Page: 83 / 150

Functional Description
MVME2502 Installation and Use (6806800R96L) 83
4.6.1 SPI Flash Memory
The MVME2502 has two 8 MB on-board serial flash. Both contain the ENV variables and
the U-Boot firmware image, which is about 513 KB in size. Both SPI flash contain the same
programming for firmware redundancy and crisis recovery. The SPI flash is programmed
through the JTAG interface or through an on-board SPI flash programming header.
For information on U-boot and ENV Variables location see
Flash Memory Map on page 98
.
4.6.2 SPI Flash Programming
The MVME2502 has three headers: a 10-pin header for SPI Flash programming, an 80-pin
header for the JTAG connectivity, and a 20-pin JTAG header for ASSET hardware
connectivity. The following options are used to program the on-board flash:

Using on-board SPI header
The MVME2502 uses the 10-pin header with a Dual SPI Flash in-circuit
programming configuration. The pin connection is compatible with DediProg SPI
Universal Pin Header.

Using 60-pin external JTAG header
An external JTAG board with a JTAG multiplexer is compatible with the
MVME2502 and is attached using an external cable. It is used to update the boot
loader in the field. Using this method, programming is done through the JTAG
interface or by using the dedicated SPI Flash programming header on the JTAG
board.

Factory Pre-Programming
Programming the SPI Flash usually takes a while. Ideally, the SPI Flash should be
pre-programmed in the factory before shipment.

ICT Programming
This programming is done on exposed test points using a bed of nails tester.
4.6.3 Firmware Redundancy
The MVME2502 utilizes two physically separate boot devices to provide boot firmware
redundancy. Although the P2020 provides four SPI Bus chip selects, the P2020 is only
capable of booting from the SPI Device controlled by chip select 0. External SPI
multiplexing logic is implemented on the MVME2502 to accommodate this chipset
limitation.
The board power should be switched on before programming. The switch S2-8
should also be powered on to successfully detect the SPI Flash chip.