Artesyn MVME4100ET Single Board Computer Installation and Use (June 2014) - Manual (Page 73)

Functional Description
MVME4100ET Single Board Computer Installation and Use (6806800K76F) 73
4.8 Local Bus Interface
The MVME4100ET uses the MPC8548E Local Bus Controller (LBC) for access to on-board flash
and I/O registers. The LBC has programmable timing modes to support devices of different
access times, as well as device widths of 8, 16, and 32 bits. The MVME4100ET uses the LBC in
GPCM mode to interface to two physical banks of on-board flash, an on-board Quad UART
(QUART), an MRAM, and on-board 32-bit timers along with control/status registers. Access
timing for each device type is programmable and depends on the device timing data found in
the VPD during initialization.
A hardware flash bank write protect switch is provided on the MVME4100ET to enable write
protection of the NOR Flash. Regardless of the state of the software flash write protect bit in
the NOR Flash Control/Status register, write protection is enabled when this switch is ON.
When this switch is OFF, write protection is controlled by the state of the software flash write
protect bits and can only be disabled by clearing this bit in the NOR Flash Control/Status
register. Note that the F_WE_HW bit reflects the state of the switch and is only software
readable whereas the F_WP_SW bit supports both read and write operations.
The MVME4100ET provides a dual boot option for booting from one of two separate boot
images in the boot flash bank which are referred to as boot block A and boot block B. Boot
blocks A and B are each 1 MB in size and are located at the top (highest address) 2 MB of the
boot flash memory space. Block A is located at the highest 1 MB block and block B is the next
highest 1 MB block. A flash boot block switch is used to select between boot block A and boot
block B. When the switch is OFF, the flash memory map is normal and block A is selected. When
the switch is ON, block B is mapped to the highest address. The MAP_SELECT bit in the flash
Control/Status register can disable the jumper and restore the memory map to the normal
configuration with block A selected.
4.8.1 Flash Memory
The MVME4100ET is designed to provide 128 MB of soldered-on NOR flash memory. Two
Spansion +3.3 V devices are configured to operate in 16-bit mode to form a 32-bit flash bank.
This flash bank is also the boot bank and is connected to LBC Chip Select 0 and 1.
A second bank of NAND flash, up to 16 GB, connected to LBC Chip Select 2 is also included. The
VPD flash packet(s) will determine which devices are populated and the size of the devices.
Programming details can be found in the MVME4100ET Single Board Computer Programmer’s
Reference manual.