Psion Organiser II

Psion Organiser II

A Psion Organiser II with the sliding cover retracted
Specifications
Developer	Psion Ltd
Manufacturer	Psion Ltd
Type	Handheld pocket computer
Released	1986
Discontinued	Early 1990s
CPU	Hitachi HD6303X 8-bit CMOS @ 0.9216 MHz (3.6864 MHz crystal ÷ 4)
Memory	8 KB (CM), 16 KB (XP), 32 KB (LA / LZ) or 64 KB (LZ64) RAM; 32 KB or 64 KB ROM
Storage	Two side slots for Datapaks, Rampaks and Flashpaks; one top slot for devices
Display	2 × 16 characters (CM/XP/LA) or 4 × 20 characters (LZ/LZ64), dot matrix LCD
Sound	Piezoelectric buzzer
Dimensions	142 mm × 78 mm × 29.3 mm (cover closed)
Weight	Approximately 225 g with battery
OS / Firmware	Psion Organiser II operating system in ROM, with OPL
Predecessor	Psion Organiser
Model no.	CM, XP, XP(LA), Multilingual XP(LA), LZ, LZ64, plus POS 200, P250, P350, P432 and P464 industrial variants

The Psion Organiser II is the machine that made Psion's name. Launched in 1986, it replaced the Series 1 with a real operating system, a two-line display, a programming language (OPL), a top slot for peripherals, and a range that eventually stretched from an 8 KB consumer model to ruggedised point-of-sale terminals used in industry well into the 1990s.

Internally it is an 8-bit CMOS computer: a Hitachi HD6303X processor, a semi-custom control IC that handles memory decoding, the real-time clock, keyboard polling and power sequencing, and a Hitachi HD44780/HD44100 LCD driver pair — all surface-mounted on a system board, with a separate through-hole power supply board joined to it by a 27-way strip connector.

Models

Three Organiser IIs. Left: closed, with the sliding cover in place. Centre: a two-line model. Right: a four-line LZ — the taller screen aperture is the quickest way to tell them apart.

Consumer models

The first Series II machines appeared in 1986 with a two-line display. The CM had 8 KB of RAM and the XP 16 KB; the XP was almost immediately upgraded to 32 KB and, although the casing still said XP, that machine is usually called the LA. All of these had a 32 KB ROM. A multilingual XP was later produced with an extra two 16 KB ROM banks — 64 KB in total — to hold eleven languages.

In 1989 Psion introduced the four-line machines. The LZ has 32 KB of RAM and the LZ64 64 KB (32 KB plus two 16 KB banks). They look almost identical to the earlier machines apart from the slightly taller screen. All were multilingual, normally English plus two others.

Consumer models

Model	ROM	RAM	Display	Notes
CM	32 KB	8 KB	2 × 16	The entry model
XP	32 KB	16 KB	2 × 16	Short-lived
XP (LA)	32 KB	32 KB	2 × 16	Cased as an XP; by far the commonest two-line machine
Multilingual XP (LA)	64 KB	32 KB	2 × 16	Eleven language options
LZ	64 KB	32 KB	4 × 20	1989; three languages
LZ64	64 KB	64 KB	4 × 20	32 KB plus two 16 KB banks

POS and industrial variants

Psion produced a series of point-of-sale and industrial machines. A POS model does not show a menu when switched on: it looks on the fitted packs for a procedure called BOOT and runs it. If it cannot find one it displays "PACK?" or "INSERT PACK?" briefly and switches off again. Many have non-standard keyboards.

POS and industrial variants

Model	ROM	RAM	Display	Keyboard
POS 200	32 KB	16 or 32 KB	2 × 16	Numeric
Alpha POS 200	32 KB	16 or 32 KB	2 × 16	Alphanumeric
P 250	32 KB	16 or 32 KB	2 × 16	Full
P 350	32 KB	96 KB	2 × 16	Full
P 432	64 KB	32 KB	4 × 20	Full
P 464	64 KB	64 KB	4 × 20	Full

A POS machine that "switches itself off immediately" is not faulty — it is looking for a BOOT procedure it cannot find.

Identifying your machine

Everything can be read out from the calculator. Select CALC from the main menu and evaluate the following:

Identification by PEEKB

Expression	Returns
PEEKB(-24)	The model
PEEKB(-25)	The language option
PEEKB(-23)	The ROM version, as a binary-coded decimal — $46 means version 4.6
PEEKB(8441)	The version of a top-slot device's software (press ON/CLEAR at the main menu first, to make sure it is loaded)
PEEKB(8421) / PEEKB(8431)	Version of a bootable pack in slot B: or C: respectively
8*PEEKB(8418) / 8*PEEKB(8428)	The size of the pack in slot B: or C:

PEEKB(-24) — model

Value	Model		Value	Model
0	CM		129, 130	POS 200
1	XP		65, 66	Alpha POS 200
2	XP (LA), or Multilingual XP (LA)		17, 18	P 250
14	LZ		20	P 350
13	LZ64		30 / 29	P 432 / P 464

PEEKB(-25) — language

Value	Language options
255	Not set (earliest versions)
0 / 1 / 2	English only / French only / German only (CM, XP, LA)
128	Eleven languages (Multilingual LA)
129	English, French, German (LZ / LZ64)
130	English, Italian, Spanish (LZ / LZ64)
131	English, Swedish, Danish (LZ / LZ64)

ROM versions run 2.4 to 2.6 on early CM/XP machines, 3.0 to 3.7 on CM/LA, 3.8 on the POS 350, and 4.2 to 4.6 on the LZ and LZ64.

System board

The system board is a CMOS 8-bit computer carrying the processor, ROM, RAM, LCD drivers and the control IC, with the keyboard contacts printed directly on it. All the ICs are surface-mount, and there are eight IC positions, some of them optional.

System board devices

Position	Device	Function
IC1	HD6303XFP (80-pin flat pack)	8-bit CPU derived from the 6800 family, 0.9216 MHz
IC2	HD44780 (XP), HD66780 (LZ)	Master LCD driver with character-generator ROM and display RAM
IC3 (and IC9 on LZ)	HD44100H (XP), HD66100 (LZ)	Slave segment driver, extending the display width
IC4	NEC µPD65006 GB-314 (XP) or Texas Instruments CF70043 (LZ)	Semi-custom control IC — memory decode, real-time clock, keyboard polling, power sequencing, buzzer and pump control
IC5 / IC6	27C64FP (8 KB) or 27C256FP (32 KB) OTP CMOS EPROM	System firmware. IC5 always fitted; IC6 only for the two-chip 16 KB option
IC7 / IC8	6264LFP (8 KB) or 62256LFP / KM62256BLG (32 KB) static RAM, 150–250 ns	User RAM, powered at all times so it survives switch-off
X1 / XL1	3.6864 MHz crystal	Processor clock, divided by four internally
—	32768 Hz crystal	Real-time clock oscillator

The ROMs draw about 1 µA in standby and the RAMs about 2 µA, which is why data survives with the machine off.

Memory map

HD6303X memory map

Range	Assignment
$8000–$FFFF	External PROM — 8, 16 or 32 KB, filled from the top down
$0400–$7FFF	External RAM — 8, 16 or 31 KB, filled from $2000 up (except the 31 KB option, from $0400)
$0100–$03FF	External I/O — the LCD and the control IC's latches
$0000–$00FF	Processor internal RAM and registers (192 bytes of RAM at $0040–$00FF, also retained when off)

The memory-mapped I/O block is decoded in 64-byte pages, and every one of these is address-triggered: any access at all, read or write, causes the event.

Memory-mapped I/O

Range	Function		Range	Function
$0180–$01BF	LCD ENABLE		$0300–$033F	COUNTER RESET
$01C0–$01FF	SWITCH OFF		$0340–$037F	COUNTER CLOCK
$0200–$023F	PULSE ENABLE		$0380–$03BF	NMI ENABLE
$0240–$027F	PULSE DISABLE		$03C0–$03FF	NMI DISABLE
$0280–$02BF	ALARM SET		$02C0–$02FF	ALARM RESET

Memory decode links

Six chip-select outputs (CS1_B–CS6_B) come out of the control IC, and links L1–L8 on the board — arranged as four pairs, of which only one of each pair is fitted — route them to whichever memory devices are present.

Production link options

Version	PROM	RAM	Links fitted
CM	32 KB at $8000–$FFFF	8 KB at $2000–$3FFF	L1, L4, L5, L7
XP	32 KB at $8000–$FFFF	8 KB at $2000–$3FFF plus 8 KB at $4000–$5FFF	L1, L4, L5, L7
LA	32 KB at $8000–$FFFF	32 KB at $0400–$7FFF	L1, L4, L6, L7

Keyboard

The AC key (top left) is special: it is wired straight to the control IC and to port 5 bit 7, and it is what switches the machine on. The other 35 keys form a 7 × 5 matrix. The seven outputs K1–K7 are open-drain and are pulled low one at a time; the processor reads KBD1–KBD5 on port 5 bits 2–6, and a low means a key is down. The switches are PCB pads under the keys, shorted by a conductive rubber pad.

The K1–K7 outputs are not a dedicated peripheral — they are bits 1–7 of the second stage of the real-time clock divider chain, which is why the keyboard can only be polled when the NMI latch is set to interrupt the processor directly.

The Technical Manual's published key matrix is reproduced below. Note that as printed it contains three apparent duplicates (G, S and Y) and omits E and T, so it should be verified against a real machine before being relied on:

Keyboard matrix as published

	KBD5	KBD4	KBD3	KBD2	KBD1
Port 5 bit	6	5	4	3	2
K7	D	J	P	V	S
K6	F	L	R	X	EXE
K5	G	K	Q	W	DEL
K4	C	I	O	U	Z
K3	B	H	N	Y	Y
K2	A	G	M	S	SH
K1	RA	LA	DA	UA	MODE

Even with those errors, the structure is what matters for repair: a dead row is one K output, a dead column is one KBD input.

Real-time clock and the 34-minute wake-up

The control IC contains a 27-bit divider chain split into two stages. Stage 1 is a 15-bit counter clocked at 32768 Hz, so its top bit runs at 1 Hz. Stage 2 is a 12-bit counter.

While the machine is on, the 1 Hz signal goes to the processor's NMI input and the clock is updated every second. When the machine is switched off, the 1 Hz signal is instead routed to stage 2, and when stage 2 times out — after 34 minutes and 8 seconds — it switches the Organiser on by itself, lets the processor add 34 min 8 s to its time registers, and switches off again.

That is why an Organiser left switched off still keeps good time, and it is also why a machine sitting in a drawer draws a little more power than a pure standby figure would suggest.

Display

The LCD is 32 characters as two lines of 16 (four lines of 20 on the LZ), driven at 1/16 duty. The HD44780 provides the 16 common lines and the first 40 segment lines; the HD44100 slave provides the rest. The panel connects to the board through conductive rubber connector strips — 96 connections in all, 16 commons and 80 segments. Psion's part number for the strip is 3700 0002, "LCD. CONN. F/PITH 70 × 3.8 mm".

Contrast is set by the thumbwheel, a 10 kΩ potentiometer (VR1) on the power supply board, which adjusts the negative V_LCD rail.

Power supply board

The power supply board regulates and distributes power, and also carries the signals through to the three external device connectors and the buzzer. It works from a supply of 5.5 to 11 V and delivers currents from 30 µA to 170 mA depending on state.

Supply rails

Rail	Purpose	Voltage	Typical load
VCC1	Main system board supply, always present. Keeps the real-time clock running and the RAM alive when off	3–5 V when off; 5 V ±5 % when on	30 µA off; up to 25 mA on
VCC2	System board LCD drivers	5 V ±5 % when on	~1 mA
V_LCD	Negative rail for the LCD, set by the thumbwheel	Adjustable between about +1.2 V and −3 V	100–300 µA
SVCC	Supply to the external slot devices, switched under software control	5 V ±5 %	up to 170 mA
SVPP	Secondary rail to slots 1 and 2	4.5 V normally; 21 V ±2 % pulsed when programming Datapaks	50 mA for 50 ms bursts

Operating states

State	ON_B	PACON_B	VCC1	VCC2	V_LCD	SVCC	SVPP	Total draw
1 — off	high	high	3–5 V	off	off	off	off	~40 µA
2 — on, slots off	low	high	5 V	5 V	−3 to +1 V	off	off	~25 mA running, ~4 mA asleep
3 — slots on	low	low	5 V	5 V	−3 to +1 V	5 V	4.5 V	~25 mA plus devices
4 — programming	low	low	5 V	5 V	−3 to +1 V	5 V	21 V	pulsed

The 21 V programming voltage is produced in two stages: an inductor-based pump charges a storage capacitor towards 35 V, a zener sets a READY flag once it is high enough, and a regulator then puts 21 V onto SVPP long enough to program one EPROM byte. The software must not leave the pump enabled — Psion warn that damage can occur if PULSE is left running.

The buzzer is a 27 mm piezoelectric element driven directly from the ALARM latch through a 1 kΩ resistor. It only makes a sound on transitions of that signal, so tones are produced by the software toggling ALARM set and reset. The ALARM signal is also an interlock for the programming voltage, which imposes restrictions on using the buzzer while the slots are powered.

Battery

The Organiser II runs from a 9 V PP3, which must be a low-internal-resistance type because the system draws peaks of 200 mA.

PP3 types

Type	Rechargeable	Typical capacity
Long-life alkaline	No	400–500 mAh
Nickel-cadmium	Yes	100 mAh between charges

A new cell reads up to 10.5 V off-load and falls through its life to the 5.5 V system minimum.

Packs and the top slot

A Datapak. The EPROM inside can only be erased optically, so deleted records still occupy space until the pak is UV-formatted.

The Organiser II has two side slots for storage packs and one top slot for devices such as the Comms Link, bar code readers and printers. Storage came in three forms:

• Datapaks — EPROM, in 8 KB, 16 KB, 32 KB, 64 KB and 128 KB sizes. Non-volatile and effectively permanent, but only erasable under ultraviolet light.
• Rampaks — static RAM with a backup cell, in 32 KB, 64 KB, 128 KB and 256 KB sizes. Rewritable, but dependent on their internal battery.
• Flashpaks — flash memory, 128 KB and 256 KB, using a 28F010 device.

Schematics for the 16 K, 32 K, 64 K and 128 K Datapaks, the 32 K and 256 K Rampaks, the 256 K Flashpak, the Comms Link and the ParaLink have been reverse-engineered and published by Olivier Gossuin.

Never insert or remove a Rampak with the machine powered. The backup cell has a low internal resistance, and the sudden power drop when a pack is hot-plugged — or when a hungry top-slot device is switched on — is a known cause of data corruption.

Documentation on this wiki

• Organiser II Spare Parts List v3 — Psion's own exploded diagram and component-level parts lists, including capacitor values and designators for the PSU and CPU boards.

Psion's exploded assembly diagram from the Organiser II Spare Parts List, with the numbered parts table.

General maintenance

Main article: Psion Organiser II General Maintenance

Battery leakage, pack slot contacts, the conductive keymat and the LCD's rubber connector strips are the routine concerns. See the Psion Organiser II General Maintenance guide.

Troubleshooting

Main article: Psion Organiser II Troubleshooting Guide

The Technical Manual documents the rails, the operating states and the current figures well enough for genuinely systematic diagnosis, and the community has found several faults the manual does not cover. See the Psion Organiser II Troubleshooting Guide.

Capacitor replacement

Main article: Psion Organiser II Capacitor Replacement Guide

Psion published component-level values, and the LZ/LZ64's persistent whistle is a known ageing-capacitor fault. See the Psion Organiser II Capacitor Replacement Guide.

See also

• Psion Organiser — the 1984 Series 1
• Battery Refurbishment
• Battery Explosion, Capacitor or Corrosion Damage