Omega Engineering IOP-241 - Manual (Page 25)

5. Register Descriptions
The program registers of the IOP-241 occupy eight adjacent bytes of I/O address space. These
registers must be programmed to control the operation of the IOP-241. The table below lists
the program registers along with their offsets relative to the I/O space base address at which
the IOP-241 is located:
Interrupt Acknowledge Register W 7
Interrupt Status Register R 7
Interrupt Mode Control Register R/W 6
Port C Interrupt Enable Register R/W 5
Data Port C Control Register R/W 2
Data Port B Control Register R/W 1
Data Port A Control Register R/W 0
Register Read/Write Offset
Table 5-1. IOP-241 Program Registers
Each register of the IOP-241 is discussed in detail in the following sections.
5.1 Data Port A Control Register (Base + 0)
The Data Port A Control Register contains the control bits for I/O channels DATA0 - DATA7.
Each I/O channel may be individually programmed for input by writing a '1' to the
appropriate bit of this register.
General Purpose I/O bit 0 DATA0 0
General Purpose I/O bit 1 DATA1 1
General Purpose I/O bit 2 DATA2 2
General Purpose I/O bit 3 DATA3 3
General Purpose I/O bit 4 DATA4 4
General Purpose I/O bit 5 DATA5 5
General Purpose I/O bit 6 DATA6 6
General Purpose I/O bit 7 DATA7 7
Description Name Bit
Table 5-2. Data Port A Control Register
IOP-241 Users Manual 25