Isa Memory Support; Isa Irq Support; Table 25: Available Isa Bus I/O Ranges - VersaLogic Viper VL-EBX-38ECP Hardware Reference Manual

The next table lists the I/O ranges available on the ISA bus unless there is a device claiming the
range on the LPC or PCI bus. The FPGA on the EBX-38 uses I/O addresses 0xC80-0xCCF and,
if enabled, the four COM ports that can be configured in the BIOS Setup utility to map to various
address ranges will be blocked by the FPGA from ISA I/O accesses. The FPGA always blocks
0x2E/0x2F and 0xC00 – 0xC7F for the SCH3114 Index/Data and Runtime Registers.
By default, the four COM ports in the FPGA are enabled and occupy the I/O address ranges of
0x3F8-0x3FF, 0x2F8-0x2FF, 0x3E8-0x3EF, and 0x2E8-0x2EF. The following are the I/O
address ranges available on the ISA bus when the BIOS is configured to factory defaults.

Table 25: Available ISA Bus I/O Ranges

0x0 – 0x1F

0x22 – 0x23

0x26 – 0x27

0x2A – 0x2B

0x32 – 0x33

0x36 – 0x37

0x3A – 0x3B

0x3E – 0x3F

Assuming the COM ports are disabled, the available I/O base addresses for COM ports on the
ISA bus are as follows:
Each COM port in the FPGA that is enabled will use one of these I/O base addresses and, in that
case, that 8 byte I/O range will not be available on the ISA bus. PCI devices may be assigned I/O
space, but that usually occurs at I/O address 0x1000 or higher so as to not conflict with legacy
I/O devices.
ISA M S
EMORY
The following memory addresses are available on the ISA bus:
0xA0000 – 0xB7FFF

ISA IRQ S
UPPORT
The following IRQs are supported on the ISA bus:
EBX-38 Hardware Reference Manual
0x43 – 0x4F

0x53 – 0x60

0x62

0x64

0x66

0x68 – 0x70

0x78 – 0x7F

0x90 – 0x91

0x200

0x208

0x220

0x2F8

UPPORT
0x93 – 0x9F

0xA2 – 0xA3

0xA6 – 0xA7

0xAA – 0xAB

0xAE – 0xAF

0xB6 – 0xB7

0xBA – 0xBB

0xBE-0x3AF

0x228 0x338
 
0x238 0x3E8
 
0x2E8 0x3F8
 
Expansion Interfaces
0x3BC – 0x3BF

0x3E0-0x3FF,

0x480 – 0x4CF

0x4D2 – 0x4FF

0x600 – 0xBFF

0xCD0 – 0xCF8

0xCFA – 0xCFB

0xD00 – 0xFFF

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