SERIES PMC341 PCI MEZZANINE CARD SIMULTANEOUS ANALOG INPUT MODULE
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enabled in the control register, an interrupt request will
be issued when 400 values of the Auto Zero calibration
voltage have been stored in the memory buffer. This
corresponds to 100 values for each of the four
channels enabled.
6.
Execute Write of 0001H to the Start Convert Bit at
Base A 18H. This starts the continuous mode
of conversions.
7.
Upon system interrupt, Analog input is disabled as
requested via bit-6 of the Control register. Execute
Write of 8000H to the Interrupt Register at Base
A 00H.
a)
Interrupts are disabled, and the Interrupt
request is released.
8.
Software must read the memory buffer and calculate a
Count0V value for each channel 0 to 3, by averaging
the 100 values for each channel.
Determination of the Count5V Value
9.
Execute Write of 01H to the Interrupt Register at Base
A 00H.
a)
Interrupts Enabled
10.
Execute Write of 004AH to the Control Register at
Base A 04H.
a)
Continuous Mode Enabled
b)
Auto Span Calibration Voltage Selected
(Count5V)
c)
External Trigger Disabled
d)
Analog Input is Disabled on Memory Bank
Switch
11.
Writing the Channel Enable register, Low Bank Timer
Value, and the Memory Threshold is not necessary
because they need not change from that programmed
in the previous steps.
12.
Execute Write of 0001H to the Start Convert Bit at
Base A 18H. This starts the continuous mode
of conversions.
13.
Upon system interrupt, Analog input is disabled as
requested via bit-6 of the Control register. Execute
Write of 8000H to the Interrupt Register at Base
A 00H.
a)
Interrupts are disabled, and the Interrupt
request is released.
14.
Software must read the memory buffer and calculate a
Count5V value for each channel 0 to 3, by averaging
the 100 values for each channel.
Read the Reference Voltage Value From Memory
15.
Read the reference voltage memory to retrieve the
unique reference voltage value (5VRefValue). To
obtain the reference voltage value the ASCII characters
comprising the reference voltage must be read until the
null (terminating) charact
er “00” is read. To read the
most significant digit, the Reference Voltage Access
register must be written with data value 8000H at Base
A 1CH. The data can be read by polling the
Reference Voltage Read Data/Status register. When
bit 0 of the Reference Voltage Read Data/Status
register is set to logic high, then the data on bits 15 to 8
contains the most significant digit of the reference
voltage value, represented as an ASCII character.
To initiate a read of the second memory location of the
reference voltage value, the Reference Voltage Access
register must be written with data value 8100H at Base
A 1CH. When bit 0 of the Calibration
Coefficient Status register is set to logic high, then the
data on bits 15 to 8 of this register contains the decimal
point digit of the reference voltage value.
This procedure must continue until the null ASCII
character is read from memory. The string can then be
converted into a float by using your compiler’s ATOF
function.
16.
Since Count0V, Count5V, and 5VRefValue are known,
corrected input data values can now be determined.
Start Conversion Of Differential Input Channel Data
17.
Execute Write of 01H to the Interrupt Register at Base
A 00H.
a)
Interrupts Enabled
18.
Execute Write of 0042H to Control Register at Base
A 04H.
a)
Continuous Mode Enabled
b)
Channel Differential Input Selected
c)
External Trigger Disabled
d)
Analog Input is Disabled on Memory Bank
Switch
19.
Execute Write 0001H to the Start Convert Bit at Base
A 18H. This starts the continuous mode of
conversions. Continuous simultaneous conversions of
channels 0 to 3 are implemented and corresponding
results are stored in the Memory buffer.
20.
Upon system interrupt the Memory buffer at Base
A 800H must be read. The data read should
be corrected per equation 1 of this section.
Programming Interrupts
Interrupts can be enabled for generation after the Memory
buffer contains more new data values than that set by the
Memory Threshold register. Interrupts generated by the PMC341
use interrupt request line INTA# . The interrupt release
mechanism is release on register access. That is, the PMC341
will release the INTA# signal when bit-15 of the Interrupt Register
at Base A 00H is set to logic “1”.
