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S y s t e m m a n a g e m e n t c a r d s
Descriptions
Memory
The on-board memory occupies a contiguous 32-Kbyte address space, the
base being at C8000h or D0000h (jumper selectable). All memory is 8-bit
only. The following table shows the memory map:
Offset
0000
4000
6000
The BIOS is a 12V non-sectored Flash device. Since it is not critical to the
system boot process, no jumper mechanism is present to enable an
alternative 'boot' block.
The Flash disk is a 2-Mbyte 12V part. Since the part requires a tight-
tolerance 12V rail, a DC/DC converter generates the programming voltage.
The part is protected from programming via an Apricot port.
The 32-Kbyte SRAM is for use by the BIOS as a stack or for other storage
purposes.
On card reset, the SRAM and DOS Flash are disabled, being enabled by the
BIOS through the Apricot Control Register.
I/O Map
I/O Address
0800h : write
0120h : write
0120h : read
0121h : write
0122h : r/w
0123h - 0127h
0128h - 012Fh
03E8h - 03EFh
02E8h - 02EFh
Port 80 Monitor : 0080h : write
This 8-bit port captures all diagnostic codes written by the motherboard
BIOS. The port is readable by DiagP, which can then communicate the
codes to the SMC. If the port contents are lost due to overrun by the
motherboard, there is no problem; the aim is merely to keep track of the last
value in the event that the system hangs.
13/2
Device
BIOS page, SRAM and DOS
FLASH disabled BIOS page,
SRAM and DOS FLASH enabled
DOS Flash page
SRAM
Port
Port 80 Diagnostic Port
BIOS page register
Status register
DOS Flash page register
Control register
Reserved for expansion
Diagnostic UART
COM3
COM4
= Unused portion of memory
Page Size
Total Size
32 Kbytes
128 Kbytes
16 Kbytes
8 Kbytes
2 Mbytes
8 KBytes
8 KBytes
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