WinSystems SAT-520PLUS, Руководство по эксплуатации, Страница: 21 / 50

070223 Operations Manual SAT-520PLUS 15
PC/104 Add-on Modules – The GP bus provided by the AMD Elan SC520 processor
does a reasonably good job of implementing the ISA (PC/104) bus. There are,
however, a few caveats and limitations that may not allow certain PC/104 add-on
modules to function properly.
Pin Number Pin Name Caveat/Limitation
A1 IOCHK* No bus level NMI support
B5 -5V No support for -5 volts
B8 SRDY There is no support for 0 wait state.
All bus timing is fixed by the SC520
B19 Refresh/DACK0 No support for Refresh to the ISA bus
B20 BCLK This is an asynchronous 8MHz clock
B30 OSC This is an asynchronous 14.318MHz clock
D8 DACK0 No DMA channel 0 available
D9 DRQ0 No DMA channel 0 available
D12 DACK6 No support for DMA channel 6
D13 DRQ6 No support for DMA channel 6
D14 DACK7 No support for DMA channel 7
D15 DRQ7 No support for DMA channel 7
D17 MASTER No support for alternate bus masters on the ISA bus
In additional to the table above, it must also be recognized that because of the large
complement of I/O devices onboard. There may be few, if any, bus interrupts available
to PC/104 add-on cards. In some cases turning off the onboard peripheral will free up
the interrupt for use on the PC/104 bus.
The table below show the standard interrupt assignments and if they are available,
and if the associated peripheral is disabled.
IRQ Number Peripheral Free when peripheral disabled
0 Heartbeat Tick NO
1 Keyboard NO
2 Slave PIC YES
3 COM2 YES
4 COM1 N/A
5 Unassigned NO
6 Floppy Controller YES
7 Parallel Port NO
8 RTC YES
9 COM3 YES
10 PCI Routing NO
11 COM4 YES
12 Mouse NO
13 FPU NO
14 Hard Disk NO
IMPORTANT NOTE : Due to limitation with the Programmable Address Registers
(PAR) within the SC520 processor, the I/O address range accessible via the PC/104
bus alters fairly significantly dependent upon the presence and type of video adapter
installed. When a PC/104Plus video card is installed, I/O addresses below 200H are
not accessible on the PC/104 Bus, therefore, all I/O cards must be mapped above
200H. This limitation does not exist when using a PC/104 video card, or when no
video card is present.