Psion Organiser

The Psion Organiser — retrospectively the Series 1 — is the handheld computer Psion Processors Ltd launched in 1984, and the machine that started the whole Psion line. Psion marketed it as a pocket computer with two removable "solid-state drives", and it is widely described as the first practical electronic organiser.

Psion Organiser

The Psion Organiser (Series 1) with its sliding cover removed
Specifications
Developer	Psion Processors Ltd
Manufacturer	Psion Processors Ltd
Type	Handheld pocket computer
Released	1984
CPU	Hitachi HD6301X 8-bit CMOS @ 0.9216 MHz (3.6864 MHz crystal)
Memory	2 KB RAM, 4 KB ROM internal to the CPU (14 KB total with one 8 KB Datapak)
Storage	Two Datapak / program pack slots (EPROM, 8 KB and 16 KB paks)
Display	16-character single-line dot-matrix LCD
Sound	None
Dimensions	142.0 mm × 78.0 mm × 29.3 mm (cover closed)
Weight	225 g
OS / Firmware	Psion Organiser firmware in the CPU's internal 4 KB ROM
Successor	Psion Organiser II
Model no.	Also sold as the OTG-PC and the NUME Executive Lifestyle Pocket Computer

It is a spartan machine by later standards: a single line of sixteen characters, 2 KB of RAM, a 4 KB firmware ROM inside the processor itself, and no operating system to speak of. Almost all of its capability comes from the removable Datapaks and program packs that plug into the two slots in the back.

Technical data

The following is Psion's own published specification.

Psion Organiser Series 1 — manufacturer's technical data

Item	Specification
Microprocessor	Hitachi HD6301X eight-bit CMOS microprocessor with a 0.9216 MHz clock, derived from a 3.6864 MHz crystal
ROM	4 KB, internal to the microprocessor
RAM	2 KB
EPROM	8 KB in the supplied Datapak, extendable
Total memory	14 KB with one Datapak fitted
Clock	CMOS real-time clock from a separate 32768 Hz crystal
Display	Sixteen-character alphanumeric dot-matrix liquid-crystal display, one line
Keyboard	36 keys — ON/CLEAR, MODE/HOME, FIND, SAVE, EXECUTE, SHIFT, DELETE, SPACE, << and >>, plus A–Z with numbers, arithmetic symbols and punctuation on shift
Dimensions	142.0 × 78.0 × 29.3 mm with the protective case closed
Weight	225 g as sold
Power source	Any 9 V PP3 battery. Psion state that a mains adaptor should not be used, because it may damage the Organiser.

Power consumption

Quoted in milliwatts at the 9 V battery input:

State	Power
Machine off	0.2 mW
Machine on	40.0 mW
Datapak access, one pak (during SAVE or FIND)	500 mW
Datapak access, two paks	800 mW

The clock keeps running for about fifteen seconds after the battery is disconnected, provided the machine was switched off first — long enough to change a battery without having to reset the time. The Organiser also switches itself off after five minutes with no key pressed.

Inside the machine

The Organiser is built as two boards joined by a ribbon and a pair of pin headers, an arrangement it passed on to the Organiser II.

"PSION PROCESSOR" board

The processor board is surface-mount and carries:

• HD6301X0F — the Hitachi CPU, in a flat pack, with the 4 KB firmware masked into it
• HD44780A00H — the Hitachi LCD controller, the same family part the Organiser II uses
• HEF4081BT (quad AND), HEF4011BT (quad NAND), HEF4013BT (dual D flip-flop), HEF4040BT (12-stage counter) and HEF4060BT (14-stage counter with oscillator) — discrete CMOS glue logic
• Two crystal cans, for the 3.6864 MHz processor clock and the 32768 Hz real-time clock

The reverse of the same board carries the gold-plated interdigitated keyboard pads that the conductive rubber keymat shorts, and the LCD module clamps to its edge.

That discrete-logic arrangement is the main architectural difference from the Organiser II, which replaced all of it with a single semi-custom control IC.

"PSION POWER" board

The power board is conventional through-hole leaded construction — quarter-watt resistors, TO-92 transistors and leaded electrolytics — which makes it far friendlier to work on than the Organiser II's surface-mount power board. It carries an LM324N quad op-amp at IC1, the VR1 contrast thumbwheel, a reference diode marked RD1, a zener marked ZN1, and electrolytics at designators including C1, C3, C5, C6, C8, C9 and C10.

Those designators, and the LM324-plus-reference-diode arrangement, are the same scheme Psion documented for the Organiser II power supply board, which suggests the two are closely related designs. Psion never published a Series 1 schematic or parts list, so the Organiser II Technical Manual's power supply chapter is the best available guide to how this board works — but the component values must be read off your own board. See the Psion Organiser Capacitor Replacement Guide.

Datapaks

A Psion Datapak. Data is stored in EPROM, so nothing can be electrically erased — deleted records are merely marked as skipped and continue to occupy space.

The two slots in the back of the machine are what Psion called solid-state drives. Drive one came with a real Datapak; drive two came with a dummy pak fitted to protect the contacts, and Psion's instruction is to keep a real or dummy pak in each slot at all times.

For the Series 1, Datapaks came in 8 KB and 16 KB only.

8 KB Datapak — manufacturer's specification

Item	Specification
Capacity	8 KB — 10,900 characters of packed data
Storage medium	EPROM
FIND time	Worst case with a full pak, 5 seconds maximum
SAVE time	4–8 characters per second, depending on battery age
Data retention	Mean time to failure 50 years at temperatures up to 100 °C
Formatting	30 minutes in a Psion Formatter prepares a pak for re-use
Life	Can be formatted up to 100 times

Because the storage is EPROM, erasing a record does not free the space — it is only marked so that the Organiser skips it. The only way to reclaim a pak is to erase the EPROM optically: the Psion Formatter shines ultraviolet light through the window in the chip for half an hour. The white label on the underside of a pak is there to keep light off the die, and has to be removed before formatting.

Program packs are different again. Most Series 1 software packs use a special board silkscreened "PROGRAM PAC" in which the programming voltage (Vpp) line is not connected, so the pack cannot be written to even though it contains an EPROM. The Link-Up Pack and the Software Pack used ordinary Datapaks so that settings and programs could be saved onto the same pak.

Using the machine

The Organiser has no menu system. It has a set of activities, shown as an indicator to the left of the current line:

Activity	Purpose	How it is selected
ENTER	Neutral state for typing and editing	MODE/HOME
SAVE	Write the current line to a Datapak as a record	SAVE key (press again to alternate between SAVE1: and SAVE2:)
FIND	Search a Datapak for a record	FIND key
CALC	Calculate the current line	MODE/HOME
OFF	Switch off	MODE/HOME, then EXECUTE
ERASE	Mark a retrieved record as deleted	MODE/HOME, but only while a found record is displayed

Nothing happens until EXECUTE is pressed. Useful limits and behaviours:

• A line may be up to 200 characters long. If typing stops having any effect, that limit has been reached.
• A search clue may be 1 to 15 characters, and may occur anywhere in the record. Prefixing it with an asterisk anchors it to the start of the record, so *SUS finds SUSAN SMITH but not CONSENSUS.
• An empty search clue steps through every record in the pak.
• The calculator handles numbers of up to seven digits, exponents from 1.000000E-99 to 9.999999E99, and two levels of brackets.
• A calculated answer is not part of the current line and cannot be saved — unless you edit it, at which point it becomes the line and can be saved like anything else.

Error messages

Message	Meaning
LOW BATTERY	Battery voltage too low. Do not SAVE after seeing this — a failed write can spoil the remaining space in the pak.
DATAPAK FULL	The pak cannot accept the record. Remember that erased records still occupy space.
DATAPAK ERROR	The Organiser cannot access the pak. Normally means physical damage, or a write attempted after a LOW BATTERY warning. Existing records can usually still be read, so transfer them to another pak.
NOT FOUND	The search clue does not occur in that pak.

Variants

Two rebadged versions were produced:

• OTG-PC — the "On-The-Go Pocket Computer", distributed in the United States by Superior Systems Inc. The Psion logo on the cover is replaced by OTG-PC, the keyboard lettering differs slightly, and it uses $ rather than £.
• NUME Executive Lifestyle Pocket Computer — a Norwegian nutritional-products company's branded machine, in blue rather than red styling, with a keyboard including the dollar sign and accented characters, intended to run diet-planning software.

Design registration and patent

The Series 1 was covered by UK Registered Design applications 1019736 and 1019737 — the Organiser and the Datapak respectively — and by UK patent application GB 2 161 300 A, which lapsed in 2004.

General maintenance

Main article: Psion Organiser General Maintenance

Battery leakage from the PP3, contact corrosion in the pak slots and the conductive rubber keymat are the routine concerns. See the Psion Organiser General Maintenance guide.

Troubleshooting

Main article: Psion Organiser Troubleshooting Guide

Psion's own manual carries a short troubleshooting section, and the closely related Organiser II Technical Manual explains the circuit well enough to take diagnosis a good deal further. See the Psion Organiser Troubleshooting Guide.

Capacitor replacement

Main article: Psion Organiser Capacitor Replacement Guide

All the electrolytics are on the through-hole power board, which makes a recap straightforward. No values were ever published, so they have to be read from the parts. See the Psion Organiser Capacitor Replacement Guide.

See also

• Psion Organiser II — the 1986 successor, with a proper operating system, OPL and a top slot
• Battery Refurbishment
• Battery Explosion, Capacitor or Corrosion Damage