Real Time Devices AD1200 User Manual page 5

CHAPTER 4 - BOARD OPERATION AND PROGRAMMING
BA + 0: Read Sntus/Srart Convert (Readl'\Mrire)
.........44
BA + l: Read A/D Data/Update DAC Outputs (Read/Write)
...........44
BA + 2: Reset (Write Only) ..........
...........44
BA + 4: PPI Port A - Digital VO (ReadAMrire) ................
...............4-5
BA + 5: PPI Port B - Channel8oard Functions Select (Readflilrite)
..................4-5
BA + 6: PPI Port C - Digital VO (Readflilrire) ................
................4-5
BA + 7: 8255 PPI Conrol Word (Write Only) ...........
.......................4-5
BA + 8: SZl4TimerlCounrer0 (ReadAMrite)
...............4-7
BA + 9: 8254 Timer/Countor I (Read/lMri9
...............4-7
BA+ l0: 8254Timer/Counr€r2(ReadAMrite)
.............4-7
BA+ 11: S254ConrolWord(WriteOnly)...........
.......4-7
BA + 12: D/A Converter 1 LSB: ADA1200 (Wrire Only) ..........
......4-g
BA + 13: D/A Converter 1 MSB: ADAI200 (Wrire Only) ...........
.........................4-g
BA + 14: D/A Converter 2 LSB: ADAI200 (Wrire Only) ..........
......4-g
BA + 15: D/A Converter 2 MSB: ADA12200 (Write Only) ...........
.......................4-g
Clearing and Setting Bits in
Initializing
Enabling and Disabling the Extemal Trigger .....
....................4-12
Enabling and Disabling Intemrprs
......4-12
Conversion Modes/Triggering ............
.....................4-12
Starting an A/D Conversion
..........,.....4-13
Monitoring Conversion Status @MA Done or End-of-Convert)
......................4-13
Reading the Converted Data ............
...4-13
Programming the Pacer Clock ..................
...............4-14
8259 Programmable Intemrpt Controller
.................4-16
Intemrpt Mask Register (IMR) ..........
......................4-16
End-of-Interrupt (EOI) Command
......4-16
What Exactly llappens When an Intemrpt Occurs?
.....................4-16
Using Intemrpts in Your Programs..........
................4-16
Writing an Interrupt Service Routine (ISR)
.............4-17
Saving the startup Intemrpt Mask Register (IMR) and Intemrpt vector
..........4-tg
Restoring the Startup IMR and Interrupt Vector
.....4-lg
Common Interrupt Mistakes
...............4-19
Choosing a DMA Channel
..................4-19
Allocating a DMA Buffer
...................4-19
Calculating the Page and Offset of a Buffer
............4-20
Setting the DMA Page Register...................
............4-2t
The DMA
DMA Single Mask Register
................4-Zz
Programming the DMA Controller
.....4-23
Programming the 1200 for DMA.....
.,4-23