Psion Series 5
The Psion Series 5 of 1997 is the first EPOC32 machine and the first Psion built on ARM. It introduced the sliding keyboard clamshell that defines the shape of every later Psion, and the 640 × 240 touchscreen that the 5mx and Revo inherited.[1]
 | |
| A Psion Series 5 (1997) | |
| Specifications | |
|---|---|
| Developer | Psion Computers PLC |
| Manufacturer | Psion Computers PLC |
| Type | Clamshell palmtop / PDA |
| Released | 1997 |
| Discontinued | Superseded by the Series 5mx in 1999 |
| CPU | ARM710a core in a Cirrus Logic CL-PS7110 (ARM 7100) @ 18.432 MHz |
| Memory | 6 MB ROM on a daughter board; 4 MB or 8 MB RAM |
| Storage | Internal RAM disk; CompactFlash slot |
| Display | 640 × 240 passive-matrix LCD, 16 greyscales, backlit, with a resistive digitiser |
| Sound | Speaker, microphone and a button-operated dictaphone |
| Dimensions | 170 mm × 90 mm × 23 mm |
| Weight | 354 g including batteries |
| OS / Firmware | EPOC32 |
| Predecessor | Psion Series 3c |
| Successor | Psion Series 5mx |
| Model no. | Development codename "Protea" |
Psion published a full service manual for the Series 5, and it is hosted on this wiki — see Psion Series 5 Service Manual. That makes this the best-documented machine in the whole Psion range, and much of what follows comes straight from it.[2]
Series 5 or 5mx?
editThey look almost identical, and their mainboards, screens and other internal components are different and not interchangeable.[1]
| Series 5 (1997) | Series 5mx (1999) | |
|---|---|---|
| Processor | ARM710a core in a Cirrus Logic CL-PS7110 | ARM710T core in Psion's custom "Windermere" SoC |
| Clock | 18.432 MHz | 36 MHz |
| RAM | 4 MB or 8 MB | 8 MB or 16 MB |
| Screen | 640 × 240 | 640 × 240, clearer panel |
| Screen ribbon | Series 5 type | A different part |
The screen ribbon cables are not the same, which matters because that cable is the commonest failure on both machines.[4]
Architecture
editThe Series 5 is the first Psion product to use the ERA architecture around the ARM 7100. It is built as a main PCB and a ROM daughter PCB.[2]
Clocks
editThe CPU's main clock input is 3.6864 MHz ±50 ppm from crystal X2 in fundamental mode, multiplied internally by five to 18.432 MHz (54.2535 ns). An expansion clock at that frequency is output from the ARM 7100 and used by the CompactFlash interface device, ASIC12 (IC2).[2]
That CompactFlash controller is the part the developer and Linux-porting community know as ETNA — a bespoke, essentially undocumented Psion device present in both the Series 5 and the 5mx.[3] The service manual and the community use different names; no document states in so many words that they are the same part, but they occupy the same role.
Reset
editTwo distinct resets, and knowing which is which matters when a machine misbehaves:[2]
- Power-On Reset (cold reset) — generated by a Ricoh RN5VLR20AA open-drain voltage detector (IC4) when VDD crosses a threshold set to 2.0 V ± 2.5 %. An RC network stretches the low state to give the ARM 7100 time to reset. A cold reset erases everything held in volatile storage and indicates that all power was lost and re-applied.
- User Reset (warm reset) — a switch that forms part of the lithium backup battery's negative contact, normally reachable only by opening the backup battery cover and using a pointed instrument. Held inactive high by pull-up R1, with a small capacitor C113 providing noise bypass to protect against inadvertent resets during ESD events. All user data should survive a warm reset.
Display and digitiser
editThe LCD is a 640 × 240 passive-matrix module, normally-white. All data, clock and synchronisation signals come from the ARM 7100.[2]
A separate passive resistive digitiser is assembled over it: a glass lower plate and a hardened plastic top plate, resistive ink printed on the inner faces, four electrical connections sensing resistance across the X and Y axes, and the two conductive faces held apart by very small bumps moulded into the plastic member. It connects by a 22-way flat flexible cable.[2]
The LCD's supply rails must be enabled and disabled in a defined sequence so that no residual DC is ever left across the panel — DC causes the liquid crystal to drift and eventually damages its polarisation irreversibly. The logic supply VLL comes from an ordinary port output because it needs only about 2 mA; the main high-voltage supply is an ARM 7100-controlled boost switched-mode supply with a 4-bit DAC acting as a variable resistor in the feedback path.[2]
Keyboard
edit53 keys in a conventional QWERTY arrangement, on a separate switch matrix assembly that slides out as the screen opens. It connects to the main PCB by a 22-way flat flexible cable in a 22-way ZIF connector, of which only 20 ways carry keys — the outside pins are grounded to give the keyboard membrane a ground ring for ESD protection.[2]
ROM board options
editPsion built three ROM daughter boards:[2]
| Board | Devices |
|---|---|
| ROM Board 01 | 3 × Flash devices |
| ROM Board 02 | 1 × ROM device and 1 × Flash device |
| ROM Board 03 | 2 × ROM devices |
Intermittent faults can be caused by dry or faulty joints on the daughter PCB, and Psion suggest swapping it early in diagnosis as a quick test. Any replacement must be the same OS build number and language, checkable with Ctrl+H in the System screen.[2]
Standby current
editMeasured with the processor asleep at 2.75 V:[2]
| Model | Standby current |
|---|---|
| 4 MB | 1.50 mA |
| 8 MB | 2.10 mA |
Build variants
editPsion identified each build by part number, RAM size and language — 22 options in all, from 2900-0003-01 (4 MB English) through American, French, German, Italian, Spanish, Swedish, Norwegian, Danish and Finnish variants.[2] The part number is set into the machine's serial EEPROM at Final Test, and once a unit has passed, that EEPROM is locked.[2]
"Protea"
editPsion's internal project name for the Series 5 appears throughout the service manual's own artwork and test equipment: the final test lead is labelled PROTEA_TEST_LEAD and the dummy battery DUMMY PROTEA BATTERY.[2]
Documentation on this wiki
edit- Psion Series 5 Service Manual — Psion's own 46-page manual: circuit description, exploded views with part numbers for every moulding, screw and spring, spares kits, the full disassembly and reassembly procedure, and the Final Test Fail Ticket fault codes.
General maintenance
editTroubleshooting
editScreen cable and hinge repair
editSee also
edit- Psion Series 5mx · Psion Series 5mx Pro · Psion Revo
- Psion Series 3c — the SIBO machine the Series 5 replaced
- Battery Refurbishment
References
edit- ↑ 1.0 1.1 1.2 "Psion Series 5", Wikipedia. Source for the model history, the sliding clamshell patent and designer, the display and keyboard specifications, dimensions, the CPU identification and the statement that Series 5 and 5mx internals are not interchangeable.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Psion Series 5 Service Manual, Psion Computers PLC, November 1997. Hosted on this wiki as File:Psion Series 5 Service Manual (November 1997).pdf. Source for the circuit description, clock frequencies, reset arrangements, LCD, digitiser and keyboard interfaces, ROM board options, spares kits, disassembly and reassembly procedure, standby currents and Final Test fault codes.
- ↑ 3.0 3.1 Ash Wolf (Ninji), "\"16 Shades of Grey\" — Building a Psion/EPOC32 Emulator", 27 December 2019. Source for the CL-PS7110 / ARM710a identification on the Series 5, the Windermere / ARM710T identification on the 5mx, and the ETNA CompactFlash controller.
- ↑ David Savery, "Psion Series 5MX disassembly and screen cable repair", R3UK, 2004. Source for the screen ribbon failure mechanism and the statement that the 5mx uses a different screen ribbon from the Series 5.