|
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 Sel. | 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.
|