Omega 1002 manual Registers

3.2.2Section 2

This group of registers is used by the add-on control logic. 64 bytes of I/O locations are used. Their detailed descriptions are shown below

3.2.2.1 The 8254 Registers

The 8254, programmable timer/counter, is used to generate periodic interrupts, A/D trigger and the machine independent timer. Addresses 00h, 04h, 08h and 0Ch are used to program the 8254.

Timer 0 is used as Pacer 0 and timer 1 is used as Pacer 1. Timer 2 is used as the machine independent timer (P1002_Dealy() function). Refer to Intel’s “Microsystem Components Handbook” for detailed programming information.

3.2.2.2 The DI / DO Register

Address 20h is used for DI / DO ports. Write to this port to send data to the DO register. Read from this port to input DI data.

3.2.2.3 The A/D Buffer

Address 30h is used for the A/D buffer. This is a read-only address. Reading from this port will return the data from A/D buffer. The format of A/D buffer is:

Bit15-12	Bit11-0
Analog input	A/D data
channel

Bit15-12: The channel number of the analog input. Only lower 4 bits of channel number are shown in this register.

Bit11-0: The A/D data.

30