Xycom XVME-500, Manual

Page: 51 / 104

XVME-500/590 Manual
February, 1988
3.3.2
Interrupt Acknowledge (IACK) Vector Register (Base + 83H)
The XVME-500/590 is capable of generating an interrupt at the completion of an
A/D conversion at any of the seven levels allowed by the VMEbus specification.
Interrupts are enabled by writing a logic ‘1’ to bit D3 of the status/control register.
The ability to generate module interrupts is dependent upon setting three jumpers
(Jl0, Jll, 512; see Section 2.5.3).
The Interrupt Acknowledge Vector Register is a
write-only register. It holds the vector to be driven on the VMEbus when the
interrupt generated by the input module is acknowledged. This register is accessible
at the module base a 83H.
3.3.3 Gain/Channel Register (Base + 85H)
The XVME-500/590 uses a 32-element on-board Gain RAM to store a gain factor for
each analog input channel.
Only two of the three versions of the module are
software-programmable (versions 2 & 3).
The XVME-500/590-l (as displayed in Sections 2.6.4.2 and 2.6.4.3) realizes gains in
one of two non-software methods. The first method is gain selection via jumpers.
This method allows the input channels to be programmed for a specific gain in one
range. The second method allows modifications of the fixed gain via resistor (and
potentiometer) programming.
This section is devoted entirely to the programming capabilities of the more
versatile XVME-500/590-2 and XVME-500/590-3. In these modules, one of three
gain ranges is selected via jumper-option at the time the module is installed (see
Section 2.6.4.1). For convenience, the gain ranges and factors are repeated in Table
3-3 .
Table 3-3. Input Gain Ranges and Factors
Gain Range
Initialization
Gain Factors Covered
1, 2, 5 or 10
4, 8, 20 or 40
10, 20, 50 or 100
Immediately after power-up or system-reset, the Gain RAM should be programmed
(initialized) to provide each input channel (16 DI or 32 SE) with an associated gain
factor.
Once an input channel is initialized this way, the associated gain factor
will automatically be applied when any A/D conversion occurs on that channel.
3-6
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