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4.8.3 Performing
Autocalibration
The VMIVME-3111 board implements two latching 12-bit
Digital-to-Analog Converters (DACs). One DAC adjusts the channel zero offset,
while the other adjusts the channel gain. Both of the DACs accept right-justified
12-bit data and are write-only devices. To do the actual calibration, we suggest the
method of successive
approximation
shown
in
Figures
4.8.2-1
and 4.8.2-2. This
autocalibration routine should always be performed after a power up or a system
reset.
4.9
BUS INTERRUPT CONTROL
To eliminate the requirement for polling the VMIVME-3111 board during
basic conversion sequencing, the VMIVME-3111 board is equipped to provide an
interrupt at the end of each conversion sequence. The interrupt response is
established through the INTERRUPT CONTROL and INTERRUPT VECTOR
Registers (Table 4.6.2-1) which are described in the following paragraphs. During
BOARD RESET or SYSTEM RESET, the Interrupt Control Register is cleared to
"00," and the Interrupt Vector Register is preset to "0F" (HEX). Interrupt Register
functions are summarized in Table 4.9-1 and Appendix B of this manual contains the
data sheet for the Bus Interrupter Module (BIM).
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