Jaap's Psion II Page


Date of issue: 14/1/91Document Version: 1.0

This is a supplement to the Organiser II Technical Manual.

  1. Introduction
  2. Hardware
  3. Reading
  4. Writing
  5. Formatting
  6. Write Protect
  7. The Flash Driver
  8. The Multiboot Flash Driver
  9. Other Facilities
  10. Versions
  11. Flash Datapak software versions

1. Introduction

Flash Datapaks on the Organiser represent a substantial improvement in storage technology. There are four major advantages:

This document explains the technical details that enable this new technology to be implemented.

2. Hardware

Flash Datapaks consist of either one or two Flash chips on a board with associated regulator, counters and logic. All circuitry is CMOS so reading requires very little power.

3. Reading

Flash Datapaks are paged and segmented. Segments control address lines A14 to A18 (16K byte blocks) and pages control lines A8 to A13 (256 byte blocks). So to get to the last byte requires the segment to be set, 63 toggles of the page and 255 toggles of the address. This will take in the order of 1 millisecond.

All Organiser models can read data from Flash Datapaks except CMs which are not able to recognise segmented packs.

4. Writing

Writing is done in a completely different way to EPROMs and a special software driver must be present. If the Flash driver is not present and a write is attempted a "READ ONLY PACK" error is reported.

It is impossible to quantify the power saving compared to EPROMs. It depends primarily on the length of the data being written. The longer the data the greater the saving. As a generalisation a user can expect an order of magnitude improvement though 2 orders is quite possible.

5. Formatting

Flash Datapaks can be formatted in place. To do this each byte must be written to zero and then for the one or two chips present they must commanded to erase back to FF. When doing this each byte must be checked to ensure that is has been erased properly. If not it tries another erase until either all bytes are FF or the chip is judged to have failed.

In Flash driver Version 1.3 and greater packs can be formatted by calling the OPL procedure FLSHFORM:("B",0) where the first parameter is the slot (B or C) and the second is whether a display is required. If the second is non-zero then the standard display is given otherwise the screen is not altered.

Formatting does consume a noticeable amount of power and it is suggested that a power supply unit is connected.

6. Write Protect

All Flash Datapaks have their write protect bit set to zero so that unless the Flash driver is present no writing can take place. In order that Flash Datapaks can be write protected the most significant bit of byte 8 of the header is used as the alternate write protect bit. When a pack is freshly formatted it is always 1 (i.e. write enabled).

The format of the header is basically the standard bootable header:


bit 0Not used, always 0
bit 1EPROM (i.e. not RAMPAK) always set to 1
bit 2PGCPK always set to 1 as paged
bit 3RDWRT always set to 0
bit 4BOOT generally set to 0 as pack bootable
bit 5COPYPK generally set to 1 as pack is copyable
bit 6NYIMPL set 0 to indicate flash
bit 7MK1PAK set to 0 as not MKI pack
The default type byte is $26.
SIZE$20 for 256K pack.
BOOT$19 default
RANDOM WORDThe most significant bit is used as the real write protect bit

7. The Flash Driver

The driver software comes as a bootable device on every standard Flash Datapak and on the Flash Formatter packs. It is different from other drivers in that it is permanent, it does not get removed when On/Clear is pressed at the top level even if the bootable pack is no longer present.

In order to achieve this it assumes that it is the first item booted in. It has priority $F8. If something else is already booted in and not also a permanent device it will be removed from the device list. This should, of course, never happen.

To make a device permanent two alternative strategies should be followed depending on whether the code is booted in the low 7K or in the PERMCELL.

If it is booted in the low 7K then make 'dva_bot' the same as 'dva_top'. Remember both the old values. When attempting to remove check that both 'dva_top' and 'dva_bot' are equal and the same as the old 'dva_top'. Refuse if they are not. If they are then replace both with the old 'dva_bot'.

If it is booted in the PERMCELL then remember the old base value (at $2000) and make it equal to the value at $2002. When attempting to remove check that the value at $2000 & $2002 is as you left it then make $2000 the old value. Then push the address of 'al$zero' on the stack and exit (get the address by looking in the table pointed to by 'bta_vect').

To ensure that you are not booted in more than once use a bit in 'dvt_spar'. To be allocated a bit talk to Support. Flash sets bit 2 of $2178 when it is present. It re-vectors the following OS routines:


To remove the driver all other drivers must be removed (by pulling out all bootable packs and then pressing On/Clear at the top level) and REMOVE used in the FLASH menu. All other drivers must be removed to avoid re-revectoring problems. If a device is still present the REMOVE fails with the message "BAD DEVICE CALL". If other permanent drivers are released then they should be removed in this way, one at a time, and in the reverse order to which they were inserted.

This is a complete new procedure and care must be taken to explain it to users when an upgrade of the driver is released. There is no exterior indication that the driver has been upgraded.

Every time the Organiser is rebooted he name FLASH is re- inserted in the menu. This is to avoid the situation where FLASH has been deleted from the menu.

8. The Multiboot Flash Driver

The multi-boot Flash driver allows all long records following to be booted in. This means that other OPL extensions can be added without altering the Flash Driver. It is an extension to the standard Flash Driver.

It requires about 500 bytes of extra code some of which will be taken out of the PERMANENT cell. For this reason it is not included in the standard driver.

The first time it boots as well as making itself permanent, it boots all the long records (02 80 type that are assumed to be .BINs) immediately after the bootable code on the pack. The second time (i.e. when the driver is already present) it will be boot into the PERMCELL (the existing flash driver will already take up most of the lower 7K). Once it has determined that the flash driver is already present it minimises its size and boots the following long records.

To generate a pack to utilise this feature either use custom software or release 3.20 or above of BLDPACK.

WARNING: BLDPACK is unable to adjust any absolute pack addressing in the .BINs that it strings together. The main use of absolute pack addresses is for loading overlays. There are a variety of ways round this problem if it is absolutely necessary.

9. Other Facilities

MAKE - version 3.20 and above will allow Flash Datapaks to be made in the ordinary way.

FMAKE - uses the copier parallel interface to the IBM and allows 256k Flash Datapaks to be made from a 256K image.

Copier File Transfer Utilities - serial and parallel utilities in beta test, on this disk in COPIER directory.

10. Versions

V1.2 RELEASED 1st November 1990
First release.
V1.3b Not RELEASED ? January 1991
OPL call FLSHFORM supported.
Multi Boot version released.
V1.5 (FDRIVE15.BIN) & M1.5 (FDRIVM15.BIN) Released Dec 91
New versions of normal flash driver and multi-boot flash driver to support new flash chips. Also downwardly compatible. Please read following for details of upgrading versions. Note, M1.5 is the multi-boot version.

11. Flash Datapak software versions

If you have more than one Flash Datapak, they may have different versions of the controlling software. You MUST install whichever version is the latest. The original version of the software did not display a version number; subsequent versions display a version number when you select the `Flash' option. (On XPs, the number is on the end of the menu.)

To use a second Flash Datapak, first note the version of your current software, then remove the software (as explained in the Flash Datapak leaflet). Now install the software from the new Datapak, and note its version number. It will probably be the same version, or a later one. You can now use both Flash Datapaks.

The new Flash Datapak may not work if you do not do this.

In the unlikely event that the new software is an earlier version that the software from your original Datapak, remove the new software and re-install your previous software.

If you do have different versions of the software, then having installed the most recent version, you should format any Flash Datapaks which have the old version. (Otherwise, when you come to format the newer Datapak, the formatting process would copy the older version of the software from the older Datapak onto the newer one, and the newer Datapak might not work.) You can copy any data from the older Datapak - perhaps to the newer one - before formatting it.

Flash Datapak Formatters contain the same formatting software as Flash Datapaks themselves, and you can check the version number of the software in the same way. You must not use a Flash Datapak Formatter to format a Flash Datapak if the Datapak itself has a later version of the software. In this event, return your Flash Datapak Formatter to Psion for an upgrade.