PCM-3718 Series User Manual
44
Chapter 5 A/D Conversion
5.1 A/D Data Format and Status Register
Since the PCM-3718 cards use 12-bit A/D conversions, a single 8-bit reg-
ister will not accommodate all the data. The PCM-3718 cards therefore
store A/D data in two registers located at addresses BASE+0 and
BASE+1.
The A/D low byte data is stored in bits D4 to D7 (AD0 to AD3) of
BASE+0 and high byte data is stored in bits D0 to D7 (AD4 to AD11) of
BASE+1. The least significant bit is AD0 and the most significant bit is
AD11. You can read the source channel number corresponding to the A/
D data from bits D0 to D3 (C0 to C3) of BASE+0.
A/D data register format is:
The A/D status register at BASE+8 (read only) gives information on A/D
configuration and operation.
A/D status register format is
:
Bits in this register indicate the end of conversion status, single-ended/
differential input, interrupt status and the number of the channel to be
converted next. Refer to page 33, A/D Status Register, for more
information.
BASE+0 (read only) - A/D low byte & channel number
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Value
AD3
AD2
AD1
AD0
C3
C2
C1
C0
BASE+1 (read only) - A/D high byte
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Value
AD11
AD10
AD9
AD8
AD7
AD6
AD5
AD4
BASE+8 - A/D status
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Value
EOC
N/A
MUX
INT
CN3
CN2
CN1
CN0
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
