Group 2 POS Registers

Group 2 POS Register 2 (Hex 0102)   
Group 2 POS Register 3 (Hex 0103)  
Group 2 POS Register 4 (Hex 0104)


Group 2 POS Register 2 (Hex 0102) 
   This register configures the system board serial ports. 
+-----------------------------------------------+
|  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |
|-----------+-----+-----+-----------+-----+-----|
| Reserved  |EN_B |EN_A | Reserved  |IR_B |IR_A |
+-----------------------------------------------+
 EN_B: Enable serial port B
 EN_A: Enable serial port A
 IR_B: Serial port B interrupt
 IR_A: Serial port A interrupt

EN_B, EN_A  These bits enable and disable serial port B and serial port A (bit 0 in POS Register 2 of group 1 must be 1 before the serial ports can be enabled). When the bit is set to 1, the corresponding serial port is enabled; when it is set to 0, the serial port is disabled. 

IR_B, IR_A  These bits select the interrupt signal used by serial port B and serial port A. When the bit is set to 1, the corresponding serial port uses IRQ4; when the bit is set to 0, the serial port uses IRQ3. 



Group 2 POS Register 3 (Hex 0103)
   This register is used to select the address range for the serial port. 
+-----------------------------------------------+
|  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |
|-----------------------+-----------------------|
|    Port B Address     |     Port A Address    |
+-----------------------------------------------+

Address   Each four-bit field selects the address assignments for serial port A or serial port B.  The following figure shows the addresses associated with each assignment. 
          
Serial Port Addresses
                        
ADDRESS             |            ADDRESS (HEX)        |
FIELD   |ASSIGNMENT |COMPATIBLE| ENHANCED  |ARB LEVEL |
0 0 0 0 | Serial 1  |03F8-03FF | 83F8-83FF |   4620   |
0 0 0 1 | Serial 2  |02F8-02FF | 82F8-82FF |   4621   |
0 0 1 0 | Serial 3  |3220-3227 | B220-B227 |   4623   |
0 0 1 1 | Serial 4  |3228-322F | B228-B22F |   4623   |
0 1 0 0 | Serial 5  |4220-4227 | C220-C227 |   4624   |
0 1 0 1 | Serial 6  |4228-422F | C228-C22F |   4625   |
0 1 1 0 | Serial 7  |5220-5227 | D220-D227 |   4626   |
0 1 1 1 | Serial 8  |5228-522F | D228-D22F |   4627   |
1 0 0 0 | Serial 9  |3A20-3A27 | BA20-BA27 |   4628   |
1 0 0 1 | Serial 10 |3A28-3A2F | BA28-BA2F |   4629   |
1 0 1 0 | Serial 11 |3A30-3A37 | BA30-BA37 |   462A   |
1 0 1 1 | Serial 12 |3A38-3A3F | BA38-BA3F |   462B   |
1 1 0 0 | Serial 13 |3A80-3A87 | BA80-BA87 |   462C   |
1 1 0 1 | Serial 14 |3A88-3A8F | BA88-BA8F |   462D   |
1 1 1 0 | Serial 15 |3A90-3A97 | BA90-BA97 |   462E   |
1 1 1 1 | Serial 16 |3A98-3A9F | BA98-BA9F |   462F   |



Group 2 POS Register 4 (Hex 0104)
   Version level of the I/O chip containing the serial port controllers
+-----------------------------------------------+
|  7  |  6  |  5  |  4  |  3  |  2  |  1  |  0  |
|-----+-----------------+-----------------------|
|  R  |     Version     |         Reserved      |
+-----------------------------------------------+

Version   The version field is a 3-bit field that indicates the version level of the I/O chip containing the serial port controllers.

Content created and/or collected by:
Louis Ohland, Peter Wendt, William Walsh, Kevin Bowling, Jim Shorney, Tim Clarke, David Beem, Tatsuo Sunagawa, Tomáš Slavotínek, and many others.

Ardent Tool of Capitalism - MAD Edition! is maintained by Tomáš Slavotínek.
Last update: 03 Mar 2021 - Changes & Credits | Legal Info & Contact