PCM-3718 Series User Manual
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Chapter 4 Register Structure and Format
The key to programming the PCM-3718 cards is to understand the func-
tion of the 16 registers. The PCM-3718 cards require 19 consecutive
addresses in the PC’s I/O space. Each address corresponds to a card regis-
ter. The address of each register is specified as an offset from the card’s
base address. For example, BASE+0 is the card’s base address and
BASE+7 is the base address plus seven bytes. If the card’s base address is
300h, the register’s address is 307h. The following sections give detailed
information on the layout and function of each of the card’s registers.
I/O Port Address Map
The following table shows the function of each register or driver and its
address relative to the base address of the module.
Table 4.1: I/O Port Address Assignments
Address
Read
Write
BASE+0
A/D low byte & channel
Software A/D trigger
BASE+1
A/D high byte
A/D range control
BASE+2
MUX scan
MUX scan channel & range
control pointer
BASE+3
DIO low byte (DIO 0-7)
DIO low byte (DIO 0-7)
BASE+4
N/A
D/A output data (PCM-
3718HO only)
BASE+5
N/A
D/A output data (PCM-
3718HO only)
BASE+6
N/A
FIFO interrupt control (PCM-
3718HO only)
BASE+7
N/A
N/A
BASE+8
Status
Clear interrupt request
BASE+9 Control
Control
BASE+10
N/A
Counter enable
BASE+11
DIO high byte (DIO 8-15)
DIO high byte (DIO 8-15)
BASE+12
Counter 0
Counter 0
BASE+13
Counter 1
Counter 1
BASE+14
Counter 2
Counter 2
BASE+15
N/A
Counter control
BASE+17
N/A
A/D data and channels from
FIFO (PCM-3718HO only)
BASE+18
A/D data and channels from FIFO
N/A (PCM-3718HO only)
BASE+19
FIFO status
FIFO clear (PCM-3718HO
only)
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