Real Time Devices AD1200 User Manual page 21

Plz - A/D Converter StatudExternal Gate 2 Monitor (Factory Setting: EOC (A/D Converter Status))
This header connector, shown in Figure l-13, les you select either the A,/D converter status or the external gate
input of timer/counter 2 to be available for monitoring at bit 3 of ttre status word (BA + 0). The A/D converter status
provides a direct read of the t"1D converter's availability for starting convenions. This line goes low when a
conversion stafis, then goes high when the conversion is completed. Chapter 4 provides a more detailed explanation
of this status signal.
Fig. 1-13 - A/D Converter Status/External
Gate 2 Monitor Jumper, P12
S1 - Base Address (Factory Setting: 300 hex (768 decimat))
One of the most common causes of failure when you are flust rying your board is address contention. Some of
your computer's I/O space is already occupied by internal I/O and other peripherals. When the 1200 board attempts
to use I/O address locations already used by another device, contention results and the board does not work.
To avoid tttis problem, the 1200 has an easily accessible five-position DIP swirch, 51, which lets you select any
one of 32 starting addresses in the computer's VO. Should the facory sening of 300 hex (76g decimal) be unsuitabie
for your system, you can select a different base address simply by setting the switches to any one of the values listed
in Table l-2.The table shows ttre swirch settings and their corresponding decimal and hexadecimal (in parentheses)
values. Make sure that you verify the order of the switch numbers on ttre swirch (l through 5) before setting *rem.
When the switches are pulled forward, they are OPEN, or set to logic 1, as labeled on the DIp swirch package. When
you set the base address for your board, record the value in the rable inside ttre back cover. Figure l-14 shows the
DIP switch set for a base address of 300 hex (768 decimal).
Fig. 1-14 - Base Address Switch, 51
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