Specifications

EPC-3305 Hardware Reference
62
types (hard, Soft, and POR). Figure 4-2 shows the memory overlay at the top of
memory space.
Each Flash device has its own write protect mechanism. The Boot Block of the PC
BIOS can only be re-written if the write-protect jumper is installed on the board.
The Strata Flash part is write protected by bit-7 in the BIOS Control Register. A one
in this position (D7) disables write protection of the device. disabled. The next table
shows the page select mapping.
WP Write-protects user Flash banks (Not the PC BIOS Boot block). If set to
zero the user Flash banks are write protected. When set to one the user
my update any of the seven user banks of the Flash.
BC2:0 Selects one of eight Flash banks.
Power monitoring, consumption, and reset generation
The CPU board has power conditioning, monitors for board input voltages, and
generates a local reset. The power conditioning provides live insertion and removal
without damage. Monitoring of input voltages ensures operation within a legal
Figure 4-2. BIOS paging
PC
BIOS
512K
User
Flash
512K
User
Flash
512K
User
Flash
512K
User
Flash
512K
User
Flash
512K
User
Flash
512K
User
Flash
111
110 101 100 011 010 001 000
FFFF,FFFF
FFF8,0000
BC[2:0]
Strata flash
Boot Block
Flash
Table 4-12. BIOS control register
R/W Index Default D7 D6 D5 D4 D3 D2 D1 D0
R/W 0x08 0x00 WP ———BC2 BC1 BC0
Table 4-13. Flash banks
BC2 BC1 BC0 Bank
111PC BIOS (POR default)
1 1 0 512k user space
1 0 1 512k user space
1 0 0 512k user space
0 1 1 512k user space
0 1 0 512k user space
0 0 1 512k user space
0 0 0 512k user space