hpCS8900 | Modular Circuits

Introduction

This peripheral module adds Ethernet connection capabilities to an H-Storm compatible system. It uses the CS8900 10Mbit Ethernet chip from Cirrus Logic as the main interface component. The card also contains the required support electronics to connect to a 10BaseT (UTP) network and some digital interface logic to interface the Ethernet controller chip to the H-Storm bus.

The card support 10Mbit of transfer rate in each direction, using a full duplex connection. This doubles the maximum available data rate to 20Mbit per second. The card operates form a single 3.3V power supply.

Features

10MBit Ethernet support with full duplex capability
10BaseT connector on board
Three status LEDs on board
AUI interface signals are available on the H-Storm connector (interface transformer has to be provided externally)
16-bit bus interface
Indexed packet-page interface
Optional direct packet-page interface
DMA operation is not supported as the basic H-Storm connector doesn’t have such resources
Generates external wait-states

License

This document and all the accompanying design documentation (for example schematic and PCB files) are covered by the H-Storm Non-Commercial License (HSNCL).

H-Storm Non-Commercial License (HSNCL)

Redistribution and use in source or binary forms, or incorporated into a physical (hardware) product, with or without modification, are permitted for non-commercial use only, provided that the following conditions are met:

The redistribution doesn’t result in financial gain.
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in any other form must contain in printed or electronical format the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
All advertising materials mentioning features or use of this technology must display the following acknowledgment:
This product includes H-Storm technology developed by Andras Tantos and Modular Circuits.
Neither the name of Andras Tantos or Modular Circuits may be used to endorse or promote products derived from or using this technology without specific prior written permission.

ALL THE INFORMATION, TECHNOLOGY, AND SOFTWARE IS PROVIDED BY THE AUTHORS AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANDRAS TANTOS, MODULAR CIRCUITS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE OR TECHNOLOGY, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Design description

The Ethernet chip

The network interface chip used on this peripheral module is the CS8900 from Cirrus Logic. The board uses the 3.3V version of the IC. This device is a single chip 10Mbit ethernet interface that incorporates both the MAC and the PHY layers of the Ethernet network stack. It was originally designed for the ISA bus of the PC architecture but now it is one of the most popular embedded ethernet chips on the market.

The chip has direct support (through interface transformers) for 10BaseT (UTP) and AUI interfaces. The card contains the support electronics and the interface transformer for the 10BaseT interface while it provides all the connections necessary to implement an AUI interface externally.

The chip supports both 16- and 8-bit operations, though the interrupt generation function is not operational in 8-bit mode. The card supports 16-bit operation of the chip only. The chip generates wait-states to make the bus-cycles long enough. The bus-cycles must be at least 157ns long so CPU cards that cannot generate long enough access cycles must support external wait-state generation to interface with this module.

The chip supports 4 interrupt lines though only one of the IRQ lines (IRQ0) is connected on the module to the nIRQ0 line.

DMA operation that is supported by the chip is not available on the module: the standard H-Storm bus connector doesn’t have support for DMA operations.

The boot-ROM support of the IC is not supported on the module. The configuration EEPROM is optional and can be mounted on the module. The module however is fully functional without that configuration chip provided the CPU module configures the module after powerup.

The Ethernet chip supports indexed and direct access to its internal packetpage memory. The module currently provides support for only indexed access with direct access available as a downloadable CPLD upgrade latter.

Support electronics

The Ethernet chip is interfaced to the H-Storm bus with a Xilinx XC9536XL CPLD. This provides easy upgrade and full support for all the required interface needs in a fast signle chip implementation.

The analog interface with the interface transformer along with an RJ45 connector is provided on board for 10BaseT Ethernet connections. The digital interface signals for an AUI interface is available on the user-defined part of the H-Storm connector. The signals for the 10BaseT interface are not available on the H-Storm connector for EMI reasons.

Three status LEDs are integrated on board: LINK, STAT and LAN. The signals driving these LEDs are also available on the H-Storm connector if external monitoring of these signals is needed.

Power requirements

The module is powered by a single 3.3V power supply. The power maximum power consumption of the module is less than 100mA.

H-Storm bus support

The hpCS8900 peripheral module is fully compatible with the H-Storm standard module specification. It supports 16-bit operations only. It does not support burst read and write operations, and generates external wait-states. It uses a single module-select signal (nSEL0) and generates interrupts on a single interrupt line (nIRQ0). The module only generates LVTTL3-compatible signals on the user-defined part of the H-Storm bus. It drives a total of 9 user-defined lines. It has no user-defined inputs.

The reset signal pulse (nRESET) must be at least 400ns wide. The bus-cycles must be at least 157ns long if no external wait-states are supported. The nWait line is assarted in less than 42ns after an active cycle is recognized.

The module presents a single CMOS gate load on all but the D0..D7 lines. On the lower 8-bits of the data-bus it presents a two CMOS gate load.

Design files

Schematic and PCB in PDF format (HSNCL)