Interconnect Port Specifications
The Newton MessagePad 2000 and eMate 300 models introduced a new
external connector. Previous models, from the original
MessagePad to the MessagePad 130 used a standard Macintosh Mini
DIN 8 port for Appletalk and serial I/O.
Well - not quite standard, since the Newton PrintPack used a
combination of a special pin and byte sequence to trigger the OS
to upload the print driver package when first plugged in.
Anyone with information on how this works should feel free to
contact me ... ;-)
The new Interconnect port provides access to the
serial/Appletalk port, audio in and out, DC power and
auto-sensing of docking.
It is physically a 26 pin, dual-sided flat connector with a
metal, D-shaped housing (presumably earthed). The
MessagePad 2000 has a recessed male connector behind small
door on one end of the device.
The following was (almost) anonomously posted to
comp.os.newton.programmer in June 1997. It appears to
be a copy of the Apple documentation.
Newton Interconnect Port
Hardware Specification for the MessagePad
Draft Preliminary, Confidential. ©1997 Apple Computer, Inc. 5/23/97
This document describes the Newton Interconnect Port. This port was
designed to connect the MessagePad to a a variety of peripherals and
devices, such as: a simple AppleTalk serial cable connection, a wireless
communications device connection port, and a complex docking port for a
desktop dock that provides audio I/O capabilities.
Because of the wide array of devices that may be connected to the
MessagePad, the Newton Interconnect Port has been designed with the
flexibility needed to accommodate the majority of such devices. There is
no minimum set of required signals: a device could, for example, use only
audio out to provide a connection to a set of amplified speakers.
The Newton Interconnect Port contains the following groups of pins:
- 7-pin AppleTalk/Local Talk interface with handshaking signals, using
the Serial Communications Controller Channel 0. This channel is interfaced
through an LTC1323 line driver, and supports both standard RS-422 serial
and AppleTalk ports. The interface provides differential-pair data signals
and buffered versions of the handshaking signals. A detailed description
of the LTC1323 line driver is available on Linear Technology's Web site
(www.linear.com). Specifics of the RS-422 standard can be found by
searching for "RS-422."
- Serial Communications Controller Channel 3 with full control signals,
ring indicator, and enable.
- Power Adapter pins that power the MessagePad and recharge the
batteries through the Newton Interconnect Port.
- Auxiliary audio input.
- Line-level auxiliary audio output.
- An auxiliary +5V power source that can be turned on or off under
software control.
- A control input that allows an external peripheral to wake the
MessagePad system if it is in the Sleep state (i.e., all clocks are
disabled and all subsystems are shut down, with the exception of the
Digital Controller's Real Time Clock). This input can also be used to
alert the MessagePad to perform AutoDocking functions (if a dock or cable
has been inserted in the Newton Interconnect Port).
Overview of the Serial Channels
The Newton Interconnect Port provides two serial channels - 0 and 3.
Channel 0 has a LTC1323 line driver connected to the Newton Interconnect
Port, and can be used as either a serial channel or as a differential
AppleTalk connection. Channel 3 can also be used with a serial port, but
has no line driver, so developers will probably need to provide one.
A block diagram of the Newton Interconnect Port, and its channels, is
shown in Figure 1-1.
Figure 1-1 Serial Ports and Enables
| | Serial Channel 0 |
| |
|
| | (CMOS Levels) |
| RS-422 levels |
|
| Digital | <-----------------> |
LTC1323 Line Driver | <-----------------> |
Newton |
| Controller | <------------------ |
------------------------- | -------------------> |
Interconnect | -----> |
| | Serial Channel 3 |
| |
|
| | (CMOS Levels) |
| |
|
Serial Channel 0
The LTC1323 Line Driver, connecting Serial Channel 0 to the Newton
Interconnect Port, provides RS-422 level inputs and outputs. Channel 0
provides a differential pair for Receive Data (RXD+/-) and
Transmit Data (TXD+/-), as well as a pair of hardware
handshake signals (HSKi and HSKo). There is also
a General-Purpose I/O line (GPI) that can be used as a ring
indicator.
Modes Supported
Channel 0 supports the following modes:
- Async, SDLC, and LocalTalk protocols
- NRZ, MRZI or FM encoding/decoding
- Clocking modes supporting both internal and external clocking
- Data rates up to 230.4Kb/sec when using the internal clock
- Data rates of 2Mbit/sec when using external clocking
Asynchronous Capabilities
Channel 0 supports the following asynchronous capabilities:
- 5, 6, 7 or 8 bits/character
- 1, 1.5, 2 stop bits
- Odd or even parity
- Break generation and detection capability
The line driver is enabled internally by the MessagePad via a
General-Purpose I/O (GPIO) pin. When this I/O pin is not enabled, the LTC
1323 Line Driver is in shutdown mode and will not drive the internal
serial bus. The Newton OS is configured to enable the 5V power supply
whenever Serial Port 0 is selected.
Connection to a Standard Apple Serial Cable
Figure 1-2 shows the connections that convert the Newton Interconnect Port
to a standard Apple Serial Connection. The figure shows a male DIN 8
connector and the Newton Interconnect Port. Both connectors are shown as
they appear to the corresponding connectors on the peripheral.
Figure 1-2 Din 8 Connection to Newton Interconnect Serial Port 0
(Original drawing showed lines between pin connections)
DIN 8
8--7--6
5--4--3
2--1
Interconnect
13-12-11-10--9--8--7--6--5--4--3--2--1
26-25-24-23-22-21-20-19-18-17-16-15-14
Table 1-1 Din 8 Connection to Newton Interconnect Serial Port 0
| Signal Name | Newton Interconnect
Pin | DIN 8 Pin |
| HSKo | 19 | 1 |
| HSKi | 20 | 2 |
| TXD- | 18 | 3 |
| Gnd | 23 | 4 |
| RXD- | 8 | 5 |
| TXD+ | 6 | 6 |
| GPI | 7 | 7 |
| RXD+ | 21 | 8 |
Accessing Serial Channel 0
Serial Channel 0 can be accessed through communication endpoints using the
standard Newton Serial Tool, AppleTalk Tool and Modem Tool. This section
assumes that you are already familiar with the Newton Operating System's
communication architecture. See the book Newton Programmer's Guide:
Communications for an explanation of how to access Serial Channel 0.
Serial Channel 3
Serial Channel 3 is connected directly to the Newton Interconnect Port.
Because the channel is always enabled, care must be taken in its use. The
Serial Channel 3 signals are intended to be used with an external, serial
line driver, such as an LTC1323. The LTC1323 inverts some of the signals,
so if a peripheral will be connected directly to the Interconnect Port,
invertors may be required to maintain the correct signal polarity.
Accessing Serial Channel 3
Serial Channel 3 can be accessed through communication endpoints using the
standard Newton Serial Tool, AppleTalk Tool and Modem Tool. This section
assumes that you are already familiar with the Newton Operating System's
communication architecture. See the Newton Programmer's Guide:
Communications for an explanation of how to access Channel 3.
Audio
The Newton Interconnect Port has both Audio Out and Audio In capabilities.
These can be used to connect to auxiliary audio devices.
AudioOut is a single-ended signal at line level, referenced
from AGND. AudioOut is capable of driving
impedance loads down to 1K Ohm. The Analog Controller output's audio to
either the internal speaker, the AuxAudioOut pin, or both.
See Table 1-2 for the output audio parameters.
Table 1-2 Audio Out Specification Parameters
| Parameter | Min | Typical | Max |
| Full Scale Output Voltage |
0.85 V peak |
1.0 V peak |
1.15 V peak |
| Instantaneous Dynamic Range (Attenuation at 0dB) |
65 dB |
68 dB |
--- |
| Frequency Response (7.2 kHz Word Rate) |
-0.6dB |
--- |
0.6dB |
| Frequency Response (21.6 kHz Word Rate) |
-0.8dB |
--- |
0.6dB |
| Programmable Output Level Attenuation |
-102.4dB |
--- |
0dB |
| Gain Step Size |
-- |
2.49dB |
--- |
| Gain Drift |
--- |
3.50ppm/C |
--- |
| Common Mode Output Voltage |
--- |
1.0V |
--- |
| Output Impedance |
--- |
10W |
--- |
| Load Impedance |
1kW |
--- |
--- |
| Short Circuit Current Limit |
--- |
--- |
50mA |
| Total Harmonic Distortion at -0.5 dB Full-Scale Level |
--- |
0.05% |
0.07% |
AudioIn is a single-ended signal at line level, referenced
from AGND. The Analog Controller can accept input from either
the internal microphone or the Newton Interconnect Port.
Audio In Specification to be supplied
Dock Attached
The Newton Interconnect Port provides a single control signal,
prodDockAttach, that can be used to perform two functions:
wake the system from the Sleep state, or allow the MessagePad to detect
the presence of a dock and perform autodocking connection functions with a
desktop machine. prodDockAttach is a General-Purpose I/O
(GPIO) signal that the MessagePad configures as an active-low input.
Waking the System
If the MessagePad is in the Sleep state, it can be awakened by pulsing the
prodDockAttach signal low for approximately 1msec.
prodDockAttach must conform to the 3.3V CMOS voltage levels
for logical high and low. This signal is normally held at a CMOS-level
logical high by a pullup resistor. Enable this signal by connecting it to
either the connector ground or to an open-drain ground that will pull it
below 0.5V. The maximum current that this signal will source is 10mA.
If the MessagePad is awake, the pulse is ignored. Timing for the
prodDockAttach signal to wake the system is shown in Figure
1-3.
Figure 1-3 System WakeUp Timing
| | |<--- tWAKE --->| |
|
| prodDockAttach ---- | \______________/ |
--------- |
Table 1-3 System WakeUp Timing
| Parameter | Description | Min | Max |
| tWake | Wake Up Pulse Width | 1 msec |
2 msec |
AutoDocking
The prodDockAttach signal can also be used to alert the
system that an external system peripheral has been attached to the
MessagePad and that autodocking should be performed.
To perform autodocking, the prodDockAttach signal must be
driven low, and must remain low until the dock is removed. The signal must
remain low for at least 10msec to be recognized by the OS as a docking
event.
If the unit is in the sleep state, the unit will awake once the
prodDockAttach signal has been asserted. Timing is shown in
Figure 1-4.
Figure 1-4 AutoDocking Timing
| | |<------ tDock ----->| |
| |<------ tDock ----->| |
| prodDockAttach ---- | \_________________ |
____/ | ----------------------------- |
| | Newton OS Validates ^ |
| Newton OS knows the ^ |
| | Autodock Event |
| autoDock Event is over |
Table 1-4 AutoDocking Timing
| Parameter | Description | Min | Max |
| tDock | prodDockAttach debounce time | 10
msec | -- |
Power Adapter Signals
The Newton Interconnect Port allows an external power source, such as an
AC Power Adapter, to source 2-cell or 4-cell devices. The 2-cell devices
are sourced through PowerInPos2, and 4-cell devices are
sourced through PowerInPos4. All MessagePads built to date
are 4-cell devices, so PowerInPos2 is not connected.
The Power Adapter is connected to five pins on the Newton Interconnect
Port. The Power Adapter's positive voltage is applied to the
PowerInPos4 signal on pins 2 and 14. The Power Adapter's
ground is applied to the PowerInNeg signal on pins 3, 15, and
16.
Besides powering the unit, a Power Adapter can also charge the internal
batteries (if a rechargeable battery pack is installed and properly
detected).
Design specifications for a Power Adaptor that can source power to the
MessagePad are described later in this document.
Connector Pinout
The following figures and tables illustrate the location of the signals on
the Newton Interconnect Port. The connector pinout numbers are shown as
they appear when looking into the respective connectors.
Figure 1-5 Newton Interconnect Port - MessagePad Side
-----------------------------------------
|1---2--3--4--5--6--7--8--9-10-11-12-13|
|14-15-16-17-18-19-20-21-22-23-24-25-26|
\--------------------------------------/
Figure 1-6 Newton Interconnect Port - PeripheralSide
-----------------------------------------
|13-12-11-10--9--8--7--6--5--4--3--2--1|
|26-25-24-23-22-21-20-19-18-17-16-15-14|
\--------------------------------------/
Table 1-5 Newton Interconnect Port Pin Assignments
| Pin Number | Signal Name |
I/O | Signal Description |
| 1 | PowerInPos2 | I | Positive
Power Adapter Input Voltage (2-cell systems) |
| 2 | PowerInPos4 | I | Positive
Power Adaptor Input Voltage (4-cell systems) |
| 3 |
PowerInNeg | I | Positive Adaptor Input
Ground |
| 4 | auxAudOutPos | O | Audio
Out (capable of driving a 1KW load) |
| 5 | AGnd | O |
Auxiliary Audio Ground |
| 6 | SerialTXdP | O | Serial
Channel 0 TX+ |
| 7 | SerialGpi | | Serial
Port/General Purpose Input |
| 8 | SerialRXdN | I | Serial
Channel 0 RX- |
| 9 | Chan3TXd3 | O | Serial
Channel 3 transmit |
| 10 | PortSel | O | Selects
between Newton Interconnect Port and internal Serial Slot |
| 11 | dock5V | O | +5 Volt
Supply |
| 12 | Chan3NotDTR | I | Serial
Channel 3 Data Terminal Ready |
| 13 | ModemNotCTS | O | Serial
Channel 3 Clear to Send |
| 14 | PowerInPos4 | I | Positive
Power Adaptor Voltage (4-cell systems) |
| 15 | PowerInNeg | I | Power
Adaptor Ground |
| 16 | PowerInNeg | I | Power
Adaptor Ground |
| 17 | auxAudioIn | I | Audio
Input |
| 18 | SerialTXdN | O | Serial
Channel 0 TX- |
| 19 | SerialHsko | O | Serial
Channel 0 Handshake Out |
| 20 | SerialHski | I | Serial
Channel 0 Handshake In |
| 21 | SerialRxdP | I | Serial
Channel 0 Rx+ |
| 22 | Chan3Rxd3 | I | Serial
Channel 3 RX |
| 23 | dGND | O | Digital
Ground |
| 24 | Chan3RI3 | I | Serial
Channel 3 Ring Indicator |
| 25 | ModemNotRTS3 | | Serial
Channel 3 Not Request to Send |
| 26 | prodDockAttach | |
Wakeup/Docking Signal |
Table 1-6 Newton Interconnect Port Signal Groups
| Power Signal Name | Pin | I/O | Signal Description |
| PowerInPos2 | 1 | I | Positive
Power Adaptor Input Voltage 2 Cell Systems |
| PowerInPos4 | 2, 14 | I | Positive
Power Adaptor Input voltage 4 Cell Systems |
| PowerInNeg | 3, 15, 16 | I | Power
Adaptor Input Ground |
| dGND | 23 | I | Digital
Ground |
| dock5V | 11 | O | +5 Volt
Supply |
| Audio Signal Name | Pin # | I/O | Signal Description |
| auxAudOutPos | 4 | O | Line Level
Audio Out |
| auxAudioIn | 17 | I | Audio Input
|
| AGnd | 5 | O | Audio Ground
|
| Serial Port 0 Signal Name | Pin
# | I/O | Signal Description |
| SerialTXdP | 6 | O | Serial
Channel 0 TX+ |
| Serial Gpi | 7 | I | Serial Port 0
General Purpose Input |
| SerialRXdN | 8 | I | Serial
Channel 0 RX- |
| SerialTXdN | 18 | O | Serial
Channel 0 TX- |
| SerialHsko | 19 | 0 | Serial
Channel 0 Handshake Out |
| SerialHski | 20 | I | Serial
Channel 0 Handshake In |
| SerialRxdP | 21 | I | Serial
Channel 0 RX+ |
| Serial Port 3 Signal Name | Pin
# | I/O | Signal Description |
| ChanTXd3 | 9 | O | Serial
Channel 3 Transmit |
| Chan3NotDTR | 12 | I | Serial
Channel 3 Not Data Terminal Ready |
| ModemNotCTS | 13 | O | Serial
Channel 3 Not Clear to Send |
| Chan3Rxd3 | 22 | I | Serial
Channel 3 RX |
| Chan3RI3 | 24 | I | Serial
Channel 3 Ring Indicator |
| Chan3NotRTS3 | 25 | | Serial
Channel 3 Request to Send |
| IntModemSel | 10 | O | Enable for
Internal Serial Channel 3 |
| Control Signal Name | Pin # | I/O | Signal Description |
| prodDockAttach | 26 | I |
Wakeup/Docking Signal |
Output Connection for Newton Interconnect Connection
The Newton Interconnect Port requires a JAE 26-pin custom mating plug.
This plug is available in locking and non-locking configurations. The
non-locking configuration should be used when designing accessories that
require smooth connection and have other mechanical means of securing the
accessory to the MessagePad, such as a dock. The JAE part number for the
non-locking connector is RX04-26P1-SF1.
The locking connector configuration should be used when designing
accessories that require a more secure connection, such as a cable. The
JAE part number for the locking connector is RX04-26P-SF1.
+5 Volt Power Supply
The Newton Interconnect Port has a +5V power supply that can be used to
power external devices connected to the port. The supply is enabled by any
of the following three events:
- Channel 0 or 3 is active. Note that the channel must be turned on -
simply connecting a device to the port will not enable the supply.
- An audio signal is being played over the
auxAudioOutPos
line. Note that the supply is enabled only for the duration of the audio
signal.
- An audio signal is being recorded over the
auxAudioIn
line. Note that the supply is enabled only for the duration of the
recording.
The total 5V power budget is 500mA, which must be shared by other devices
in the system (such as PC Cards), in addition to the Newton Interconnect
Port. Of this power budget, the Interconnect Port can draw a maximum of
100mA from the 5V power supply.
5-volt Power Supply Specifications
The section specifies the DC operating conditions for the 5V power source
available on the Newton Interconnect Port.
Table 1-7 5-Volt Power Supply Voltages
| Supply | Min Voltage | Max Voltage |
| Dock 5V | 4.5V | 5.5V |
Table 1-8 Power Supply Current Specifications
| Supply | Min Voltage | Max Voltage |
| Dock 5V | --- | 100mA |
Power Adapter
This section defines the electrical criteria that a power adapter for the
MessagePad must meet. The power adapter can be connected to the MessagePad
via an external power adapter jack, other internal connectors, or the
Newton Interconnect Port. When a power adapter is attached to any of these
connections, and to an AC power source, it supplies the power to the
system and can recharge batteries. If the power adapter is connected to
the system, but not connected to an AC power source, it will draw a
maximim of 100uA from the batteries.
DC Output Requirements
The output of the adapter must be designed to appear as a Thevenin
equivalent source with an open circuit voltage of 6.75V to 7.50V, and have
a source resistance of 0.2 Ohm to 0.4 Ohm over an output current range of
5mA to 1300mA.
When the current is below 5mA, the source voltage may not exceed 7.7V. The
output from the adapter must be current-limited to between 1.1A and 1.3A,
over the input voltage range of 4.5V to 7.0V.
Below an output of 4.0V, the current limit may be folded back or stepped
back without damage. The following table gives the acceptable output range
for several load conditions
Table 1-9 Constant Current Mode
| Output Current (mA) | Min.Voltage
Limit (VDC) | Max.Voltage Limit (VDC) |
| 5 | 7.27 | 7.50 |
| 500 | 7.07 | 7.50 |
| 1000 | 6.87 | 7.50 |
| 1300 | 6.75 | 7.50 |
Table 1-10 Constant Voltage Mode
| Output Voltage (VDC) | Min.Current
Limit (mA) | Max.Current Limit (mA) |
| 7.50 | 1100 | 1300 |
| 7.00 | 1100 | 1300 |
| 5.60 | 1100 | 1300 |
| 4.00 | 100 | 1300 |
| 0.00 | 0 | 1300 |
Table 1-11 Other Electrical Requirements
| Parameter | Nominal | Max. |
| Ripple peak-to-peak | - |
100 mV |
| Leakage Current VIN | - |
0.75 mA |
| Instantaneous Over Voltage Protection | 10.0 V |
12.0 V |
Figure 1-7 shows the Power Adapter's acceptable operating region.
Figure 1-7 Power Adapter Operating Range-Typical
(Omitted - too complex)
(The Newton Interconnect Specification was supplied with photocopies of
the original engineering drawings of the Interconnect plug. Contact Apple
Licensing if you need copies).