B&B Electronics ATXWDT, ATRWDT manual Address Switches

Switch positions 1 - 7 of S1 configure the I/O address of the WDT. Switches represent a binary 0 in the ON position, a binary 1 when OFF. Least significant bit (LSB) and most significant bit (MSB) are labeled on the card. Table 1 shows the numerical weight and electrical connection of each switch.

Table 1. Address Switches

S1 Position	7	6	5	4	3	2	1
Bus	SA9	SA8	SA7	SA6	SA5	SA4	SA3
Connection
Decimal	512	256	128	64	32	16	8
Weight
Hex Weight	200	100	80	40	20	10	8

Any I/O address may be used, but it is important that no other device in the host computer use that address. Table 2 is a list of frequently unused I/O addresses. In most cases, the WDT can be set to one of these addresses.

Table 2. Frequently Unused Port Addresses

Base Hex	Binary	Switch	I/O Space
Address	Equivalent	Settings	Description
		MSB LSB
200	1000000000	1000000	game port
208	1000001000	1000001	game port
300	1100000000	1100000	prototype
308	1100001000	1100001	prototype
310	1100010000	1100010	prototype
318	1100011000	1100011	prototype
380	1110000000	1110000	SDLC
388	1110001000	1110001	SDLC
3A0	1110100000	1110100	bisync comm
3A8	1110101000	1110101	bisync comm

4 Documentation Number ATxWDT-1303

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