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Functional Description
3
Base Module Feature Register
The Base Module Feature Register contains the details of the MCP750
single-board computer’s configuration. It is an 8-bit read-only register
located on the base board at ISA I/O address $0802.
SCCP
∗
Z85230 ESCC present. If set, there is no on-board synchronous
serial support (the ESCC is not present). If cleared, the Z85230 ESCC is
installed and there is on-board support for synchronous serial
communication.
PMC1P
∗
PMC slot 1 present. If set, no PCI mezzanine card is installed in
PMC slot 1. If cleared, PMC slot 1 contains a PCI mezzanine card.
LANP
∗
Ethernet present. If set, no Ethernet transceiver interface is
installed. If cleared, there is on-board Ethernet support.
Serial Port Signal Multiplexing
Due to pin limitations of the J3 connector, the MCP750 multiplexes and
de-multiplexes some signals between the MCP750 board and the
TMCP700 transition module. This hardware function is transparent to the
software. The block diagram for the signal multiplexing is shown in the
Figure 3-2
:
Base Module Feature Register — Offset $0802
BIT
SD7
SD6
SD5
SD4
SD3
SD2
SD1
SD0
FIELD
Not Used SCCP
∗
Not Used PMC1P
∗
Not Used Not Used
LANP
∗
Not Used
OPER
R
R
R
R
R
R
R
R
RESET
1
N/A
1
N/A
1
1
N/A
1