The spUART peripherial contains up-to two asyncronous serial ports based on the Texas Instrument's TL16C550 or compatible chips. The port signals are available as standard logic signals (LVCMOS) and as standard RS-232 compatible signals. The soruce of the signals can be determined both by software and hardware. For high-speed operation (above 250kbps) the RS-232 drivers can be switched to high-speed mode programattically using the OUT2 signal of the serial controllers.
For other interfaces than RS-232, like IrDA or RS-485 external drivers can be mounted on the motherboard and the logic I/Os of the card can be used. For normal RS-232 operation no external drivers are required.
The card supports 8-bit bus operations only. The interrupt-signals of the two serial-port controllers are tied together and connected to the IRQ0 pin of the SIMM-Sys connector.
| Pin No. | Dir | Name | Description |
|---|---|---|---|
| 1 | O | RD | Active low read select signal. |
| 2 | O | UWE | Active low write select signal. Upper byte. |
| 3 | O | LWE | Active low write select signal. Lower byte. |
| 4 | I | RESET | Active low reset signal. |
| 5 | O | SEL0 | Active low peripherial select signal. |
| 6 | O | SEL1 | Not connected |
| 7 | O | SEL2 | Not connected |
| 8 | I | IRQ0 | Active low interrupt signal. |
| 9 | I | IRQ1 | Not connected |
| 10 | I | IRQ2 | Not connected |
| 11 | O | A0 | Address lines |
| 12 | O | A1 | |
| 13 | O | A2 | |
| 14 | O | A3 | |
| 15 | O | A4 | |
| 16 | O | A5 | Not connected |
| 17 | O | A6 | |
| 18 | O | A7 | |
| 19 | O | A8 | |
| 20 | O | A9 | |
| 21 | I/O | D0 | Data lines |
| 22 | I/O | D1 | |
| 23 | I/O | D2 | |
| 24 | I/O | D3 | |
| 25 | I/O | D4 | |
| 26 | I/O | D5 | |
| 27 | I/O | D6 | |
| 28 | I/O | D7 | |
| 29 | I/O | D8 | Not connected |
| 30 | I/O | D9 | |
| 31 | I/O | D10 | |
| 32 | I/O | D11 | |
| 33 | I/O | D12 | |
| 34 | I/O | D13 | |
| 35 | I/O | D14 | |
| 36 | I/O | D15 | |
| key | |||
| 37 | PWR | WAIT | Active low signal to introduce wait-states in the access cycles. Must be driven. with an open-collector driver. The pull-up resistor is provided on the CPU card. |
| 38 | PWR | GND | Ground |
| 39 | PWR | GND | Ground |
| 40 | PWR | VCC_3 | 3.3V nominal power supply. |
| 41 | PWR | VCC_3 | 3.3V nominal power supply. |
| 42 | PWR | VCC_2_5 | 2.5V nominal power for core supply. (not used on this card) |
| 43 | PWR | VCC_1_8 | 1.8V nominal power for core supply. (not used on this card) |
| 44 | N.C | Not connected | |
| 45 | O | DTR0 | Serial port 0 signals, RS-232 level |
| 46 | O | RTS0 | |
| 47 | I | RXD0 | |
| 48 | I | DSR0 | |
| 49 | I | CTS0 | |
| 50 | O | TXD0 | |
| 51 | O | DTR1 | Serial port 1 signals, RS-232 level |
| 52 | O | RTS1 | |
| 53 | I | RXD1 | |
| 54 | I | DSR1 | |
| 55 | I | CTS1 | |
| 56 | O | TXD1 | |
| 57 | O | lvDTR0 | Serial port 0 signals, logic level |
| 58 | O | lvRTS0 | |
| 59 | I | lvRXD0 | |
| 60 | I | lvDSR0 | |
| 61 | I | lvCTS0 | |
| 62 | O | lvTXD0 | |
| 63 | O | n_LV_SEL0 | When low, select locig-level interface. When high, selects RS-232 level interface. Pulled high on the card. |
| 64 | O | lvDTR1 | Serial port 1 signals, logic level |
| 65 | O | lvRTS1 | |
| 66 | I | lvRXD1 | |
| 67 | I | lvDSR1 | |
| 68 | I | lvCTS1 | |
| 69 | O | lvTXD1 | |
| 70 | O | n_LV_SEL1 | When low, select locig-level interface. When high, selects RS-232 level interface. Pulled high on the card. |
| 71 | O | PNPC | PnP I2C bus clock |
| 72 | I/O | PNPD | PnP I2C bus data |