Hercules-EBX CPU User Manual V1.02
Page 48
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COM 1 has the following options:
o
ISA I/O Address : 0x3F8 (default), 0x2F8, 0x3E8, or 0x2E8
o
ISA IRQ : IRQ4 (default) or IRQ3
•
COM 2 has the following options:
o
ISA I/O Address : 0x2F8 (default), 0x3F8, 0x3E8, or 0x2E8
o
ISA IRQ : IRQ3 (default) or IRQ4
o
Mode : Normal (default), IrDA, ASK_IR
Note that the two IR modes require an external IR transceiver, connected to
the two IR I/O pins located on the Utility Header (J7). See page 14 for
connection details.
COM PORTs 3&4 are handled by an external UART (XR16C2850). As such, the configuration is
handled a bit differently. The I/O Addresses are not configurable in software; rather they are
determined based on the jumper settings from J5: Add or remove a jumper from header location
“A” to change COM 3 address or location “B” to change COM 4 address. Note that the BIOS
detects these I/O settings and configures COM3 and COM4 I/O Addresses accordingly.
The IRQ’s for the two COM parts are manually selectable via jumpers on header J4 (see page
34 for details of IRQ selection). These settings must then be manually entered into the BIOS in
order for these IRQ’s to be properly configured and reported from the BIOS to the operating
system.
The Setting for RS-232 versus RS-485 modes for COM PORTs 3 & 4 is software-selectable in
the BIOS.
•
COM 3 has the following options:
o
ISA I/O Address:
J5 “A” Header location with no jumper = COM 3 has I/O Address 0x3E8
J5 “A” Header location with jumper = COM 3 has I/O Address 0x2F0
o
ISA IRQ :
Jumper settings : IRQ 3, IRQ 4 (default), or IRQ 9
o
Mode:
RS-232 (Default) or RS-485
•
COM 4 has the following options:
o
ISA I/O Address:
J5 “B” Header location with no jumper = COM 3 has I/O Address 0x2E8
J5 “B” Header location with jumper = COM 3 has I/O Address 0x3F0
o
ISA IRQ :
Jumper settings : IRQ 3 (Default), IRQ 15
o
Mode:
RS-232 (Default) or RS-485
