The spCS8900 peripherial card is a 10Mbps Ethernet controller for the SIMM-Sys project built around the Cirrus Logic CS8900 ethernet controller chip. The card provides 10BaseT and AUI connections. The AUI connector signals accessable through the SIMM-Sys connector. The AUI transformer should be mounted on the motherboard as close to the AUI connector as possible. The 10BaseT transformer however is integrated on the card. For signal-integrity reasons the 10BaseT signals are not delivered through the SIMM-Sys header but a standard connector is built on the board itself. If the application's geometry does not allow external access to this connector it is recommended to provide another connector on the motherboard and a small UTP patch-cabel to be used to connect the two connectors. The activity and link LED outputs of the chip are available on the connector. The current-limiting resistors are also provided, only the LEDs are required externaly. The power-down feature of the chip can also be switched on and off programmatically. The DMA functionality however cannot be utilized as there is no such feature available on the SIMM-Sys bus.
Development documentation, drivers and sample applications can be found on the Cirrus-Logic's WEB-site. RCS is also planning to provide sample applications and driver support for this card.
The card supports both 8 and 16-bit bus operations. It also supports both the I/O and memory-mapped modes of the chip. However as the SIMM-Sys peripherial card's window is 1kWords and the CS8900 requires 2kWords in memory-mapped mode, a simple paging is implemented on the card.
| 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 | |
| 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 | |
| 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 | I | auiDI+ | AUI Data-input signal |
| 46 | I | auiDI- | AUI Data-input signal |
| 47 | I | auiCI+ | AUI Collision-input signal |
| 48 | I | auiCI- | AUI Collision-input signal |
| 49 | O | auiDO+ | AUI Data-output signal |
| 50 | O | auiDO- | AUI Data-output signal |
| 51 | N.C. | Not connected | |
| 52 | N.C. | No connection | |
| 53 | N.C. | Not connected | |
| 54 | N.C. | Not connected | |
| 55 | N.C. | No connection | |
| 56 | N.C. | Not connected | |
| 57 | O | LANLED | Active low LED driver output. Displays LAN activity. |
| 58 | O | LINKLED | Active low LED driver output. Displays activity LINK. |
| 59 | N.C. | Not connected | |
| 60 | N.C. | Not connected | |
| 61 | N.C. | Not connected | |
| 62 | N.C. | Not connected | |
| 63 | N.C. | Not connected | |
| 64 | N.C. | Not connected | |
| 65 | N.C. | Not connected | |
| 66 | N.C. | Not connected | |
| 67 | N.C. | Not connected | |
| 68 | N.C. | Not connected | |
| 69 | N.C. | Not connected | |
| 70 | N.C. | Not connected | |
| 71 | O | PNPC | PnP I2C bus clock |
| 72 | I/O | PNPD | PnP I2C bus data |