Omega 1002 Manuale Utente

 

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 

channel 

A/D data 

 

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.