Corel Netwinder internals

General Description

The Corel Netwinder is a "single board" embedded system providing the user with:

Block Diagram



The CPU is an SA-110 with FootBridge support. This allows us to run at full SA-110 speed and still have access to all the PCI devices that we require.

The SA110 address bus connects only to the FootBridge and the boot FLASH, which converts it into the memory address bus, and PCI address.
The SA110 data bus connects only to the FootBridge, the SDRAM array and the boot FLASH.
The SA110 control bus connects only to the FootBridge.

The FootBridge manages a single DIMM socket of SDRAM, and a single Flash device for boot. All these devices operate at 3V.
The FootBridge provides:


There are 6 devices on the bus:


The VGA chip is the Cyber2000. This is an enhanced VGA accellerator chip from IGS. This chip can: We have wired the board for 2MBytes of DRAM.

The VGA is addressed through PCI I/O space ports, using similar-to-PC addresses ports.

It is connected to the video capture port so that the VGA can display a live image of the video capture source.

Video Capture

No documentation yet


The Ether100 port is managed by a Digital 21143 Ethernet controller chip. It expects to be managed by tx/rx command blocks located in main host RAM, and it expects DMA access to these commands and the associated data blocks.


The Ether10 port is managed by a Winbond '940 chip. This chip has 32k bytes of local RAM. It is NE2000 compatible.

IDE Controller

The IDE is managed by the Winbond '553 chip, which contains a "sonata" core. This core implements:


The SuperIO chip implements

Audio Services

The audio port is implemented through a SoundBlaster compatible device. This will allow us to sample/playback at any rate from 8Ks/s to 44.1Ks/s, mono or stereo.

This device has DMA access to the host memory, although the path is a bit circuitous. The SoundBlaster is on the ISA bus, and must request an ISA DMA channel. The '553 device must be set up so that the ISA DMA request goes through to the PCI DMA channel.

The SoundBlaster audio ports are connected to various devices. Audio out goes to:

The local (on-board) speaker can be muted independently of the line-out. The other output ports run constantly.

The audio in comes from:

The host can select which audio source to use.

Telephony Services

The telephony services come in two sections: local audio, and outside line.

First, the local audio can be connected to either a telephone handset or to a telephone set. The VNC has ports for connecting either. The first option allows the user to plug in a handset or headset that is compatible with most telephones. The second option allows the user to plug in a regular telephone. With a real telephone, the user has a dial pad and a "cradle" for the handset. In both cases, the audio source/sink is the SoundBlaster port.

The handset port has the ability to sense when a handset is connected. The telephone set port can tell when the phone is off-hook.

Secondly, there is another independent audio channel, wired to the outside line. This line can be connected to any telco line, in the same way a modem can be. The hardware can terminate the line, detect ringing, and source/sink audio to a high quality delta-sigma codec. The codec has several words of FIFO so that the StrongArm can burst data in and out.

From a software point of view, this codec is connected through the VideoCompression chip; this was just a matter of convenience. The VidComp chip has DMA support to move the codec audio to/from the host RAM.

Power Supply

The power supply simply takes an unregulated 9V.

Most of the central section of the board runs from a +3.3V digital and a +5V digital rail. The StrongARM bus is +3.3V and the PCI bus is +5V rail. These rails are generated by switchers off the +9V raw supply.

The StrongARM itself requires a 2V rail, which we generate by a linear drop-down from the +3.3.

Each complex chip has a 0 ohm series resistor in the supply rail so that we can measure each chip.

The analog section gets its own +5V analog rail, from a linear regulator connected to the +9V rail.

The telephone set drive comes from the raw +9V, through a current source.

During power down, only the RTC gets held over, by means of a super-cap.

The reset source is from a power supply monitor, OR'd with the push button. The reset goes to the SA-110, which forwards it to the FootBridge, which then forwards it to the PCI bus.


The VNC II fits into a modified Corel Video console.

The VNC is designed to live mostly one one 5"x9" pc board. All the connectors (listed above) are located along one of the long edges of the card. The Ether100 and modem-transformer are wired on a daughter (mezzanine) card, which gives us a second row of connectors.

The system memory is installed on another daughter card. This memory card is physically and logically a SO-DIMM SDRAM memory card, so any industry-standard memory card may be used as a substitute.

There is a tiny adapter board to hold the microphone and IR components at right angles to the main PCB, and to align the mike and IR to the plastic housing.


Freq Used by
3.57MHz SA-110
25MHz Ether100 phy chip
20MHz Ether10 chip; Ether100 controller chip
14.318/17.734MHz VGA
18.432MHz SuperIO (977)
66MHz Footbridge


Signal Direction Physical
VGA out 15 pin sub D
NTSC out out analog RCA
NTSC in in analog RCA
audio out out analog walkman jack
audio in in analog walkman jack
power in ac adapter
parallel port in/out 25 pin sub D
serial  in/out 9 pin sub D
Ethernet 100/10 in/out RJ45
Ethernet 10 in/out RJ45
handset in/out analog RJ11
telephone in/out analog RJ45
IR in/out [through front panel]
keyboard in DIN5
mouse in DIN5

Resource Assignments

Many of the chips on board have multiple virtual devices. To simplify the memory map, the following assignments are made:
Memory Map
Complicated enough that it needs its own page.
DMA channels
PCI bus master
IRQ channels
Serial channels

Russell Nelson
Last modified: Tue Jul 28 16:45:21 EDT 1998