Omega Engineering IOP-241 Data Port a Control Register Base +, Offset Read/Write Register

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:

Offset	Read/Write	Register
0	R/W	Data Port A Control Register
1	R/W	Data Port B Control Register
2	R/W	Data Port C Control Register
5	R/W	Port C Interrupt Enable Register
6	R/W	Interrupt Mode Control Register
7	R	Interrupt Status Register
7	W	Interrupt Acknowledge Register

Table 5-1. IOP-241 Program Registers

Each register of the IOP-241 is discussed in detail in the following sections.

5.1Data 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.

Bit	Name	Description
7	DATA7	General Purpose I/O bit 7
6	DATA6	General Purpose I/O bit 6
5	DATA5	General Purpose I/O bit 5
4	DATA4	General Purpose I/O bit 4
3	DATA3	General Purpose I/O bit 3
2	DATA2	General Purpose I/O bit 2
1	DATA1	General Purpose I/O bit 1
0	DATA0	General Purpose I/O bit 0

Table 5-2. Data Port A Control Register

IOP-241 Users Manual 25