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 |
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:
The VGA is addressed through PCI memory-mapped 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.
The Ether10 port is managed by a Winbond '940 chip. This chip has 32k bytes of local RAM. It is NE2000 compatible.
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 audio in comes from:
First, the local audio can be connected to either a telephone handset or to a telephone set. The VNC has ports for connecting either, see above. 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. (This feature is available only on some versions of the NetWinder)
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 the draw of 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 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) |
66.666MHz | Footbridge |