by Dr. Wolfgang Strickling
There are some ideas for a hardware extension, accessing the top slot of the Psion Organiser II. They are listed and well documented on the very useful Organiser hompage at http://members.surfeu.at/org2/org2.htm.
A further extension, based on ideas mentioned above, is my box. It provides 16 user definable parallel data output lines and 8 parallel input lines. My purpose is to register meteorologic data during solar eclipses and to control photographic cameras during the eclipse. But with special software ist is possible to use this equipment for many other hardware applications and to connect your organiser to your PC. More details about the eclipse project on my Psion eclipse page in German language.
For the slot pinout look at http://members.surfeu.at/org2/toppin.htm.
Important for me are:
the data lines SD0 .. SD7,
the SS3 (Slot Select 3) line, which is active low if slot 3 (i. e. the Top Slot) is accessed, and
the SOME, SMR and the SCK lines.
First, take a look at the circuit.
Left: the opened orgniser top slot extension box.
external plug connectors for meteorologic sensors, cameras an PC connection, internal plugs for the complete Data input and output ports. On the right side a plug for an external power supply
The two 8 bit output latches 74HC273 are addressed by the SOME and the SCK lines of the top slot, whenever the top slot is activated by a Low signal on the the SS3 line. The data input driver 74HC244 is addressed by the SMR line, if SS3 is low. To avoid organiser system crash, R1 (about 100 k) at SS3 line is required.
The adress lines can be switched on and off by the following procedures.
For port reading or writing it is important to set the DDE Register
(data direction register) to a correct value (%00 for reading and %FF for
Simple procedures for accessing the ports are (% signifies hex data, and
# hex address):
; PowerOn: C6 03 LDA B,%03 3F 62 SWI %62 ;activates Slot 3 39 RTS ; Portin: C6 03 LDA B,%03 ; First activating Slot 3, otherwise problems with execution from pack 3F 62 SWI %62 ;activates Slot 3 4F CLR A 97 01 STA A,#01 ;Set DDE to Input 72 40 17 OIM %40,#17 ;Set SS3 High 72 02 17 OIM %02,#17 ;Set SMR(pin 16) High 71 BF 17 AIM %BF,#17 ;Set SS3 low D6 03 LDA B,#03 ;Read port 3 72 40 17 OIM %40,#17 ;Set SS3 High 71 FD 17 AIM %FD,#17 ;Set SMR(pin 16) Low 4F CLR A 18 XGDX ;Return B 39 RTS ; Portout: 86 FF LDA %FF ; 97 01 STA A,#01 ;Set DDE to Output 72 40 17 OIM %40,#17 ;Set SS3 High 72 08 17 OIM %08,#17 ;Set SOME (pin 15) High 71 BF 17 AIM %BF,#17 ;Set SS3 low D7 03 STA B,#03 ;Write port 3 72 40 17 OIM %40,#17 ;Set SS3 High 71 F7 17 AIM %F7,#17 ;Set SOME (pin 15) Low 4F CLR A 18 XGDX ;Return B 39 RTS ; Portout2: 37 PSH B ;Saves B to Stack 72 40 17 OIM %40,#17 ;Set SS3 High 72 01 17 OIM %01,#17 ;Set SCK (pin 10) High ;Reactivation of Slot 3 required after SCK L -> H! C6 03 LDA B,%03 3F 62 SWI %62 ;activates Slot 3 86 FF LDA %FF ; 97 01 STA A,#01 ;Set DDE to Output 71 BF 17 AIM %BF,#17 ;Set SS3 Low 33 Pul B D7 03 STA B,#03 ;Write port 3 72 40 17 OIM %40,#17 ;Set SS3 High 71 FE 17 AIM %FE,#17 ;Set SCK (pin 10) Low 4F CLR A 18 XGDX ;Return B 39 RTS
As temperature sensors i use I2C (two line) devices, eg. DS 1621 or LM 75. The I2C line is pulled high by a 10 k resistor and if active pulled low by the 74HC273. A diode avoids collisison of high 74HC273 output and low data output of a peripheral device.
Other sensors can easily attached to the hardware box. I use a light intensity sensor (TSL 230 light to frequency converter with programmable sensitivity) or the output of a pototransistor, operating behind a shutter for wind speed measurements. These sensors provide an output frequency due to their input. A software registers the frequency and calculates light intensity or wind speed from it.
To control electronic cameras the data output lines are connected with the remote cable of the camera. My cameras take an exposure, if their remote cable is connected to GND, or if its data line is set to low. For security, a diode is inserted, keeping high (5 V) output levels off the camera. Some of them (eg. my PENTAX A3) work only with 3 V power supply.
If the camera is set to manual exposure ("B" setting), it can realise shutter times from 1/10 s and longer, my Z3 is able to expose from 1/250 s upward. For the Z3 it is necessary, to activate the camera some 100 ms befor the exposure by a second line. This is the line, which activates the exposure meter of the camera (the line, which the original PENTAX two-stage remote cable swithes first). Without this activation, the camera can only take exposures longer than 1/3 s.
You can download my software including assembler source codes here.
You find a more detailed description of my eclipse software with all these functions integrated in one program on my Psion eclipse page in German language. You can download the international eclipse software here.
There is also the possibility, to connect the psion with a parallel port
of a standard PC. I excange data from the Psion to my pc by this way.
Unfortunately i did not succeed in writing data back from PC to organiser
and the data exchange is very slow and sometimes providing errors. Simply
connect the data input lines D0 to D4 to the parallel Printer output lines
D0 to D4
(D0: Pin2, D2: Pin3, ... , D7 Pin 9) and the box's output lines D0 to D4 with the parallel input lines:
D0: Pin 15 -Error
D1: Pin 13 SLCT
D2: Pin 12 PE
D3: Pin 10 -Ack
D4: Pin 11 -Busy
As a standard parallel port has only 5 data input lines, data are excanged nibble by nibble with D4 controling handshake protocol.
A windows software (Psionlink, for Win 3.1 and higher) and PClink Psion software can be downloaded here.
© Dr. Wolfgang Strickling.
The organiser hardware extension circuit
Software for the organiser hardwarebox: boxsoftware, PC linksoftware, eclipsesoftware
An application: Psion eclipse page in German language
http://members.surfeu.at/org2/org2.htm, the ultimate Organiser II homepage. Many tips, technical information and second hand devices. Very useful!
back to my Homepage (German language)
Last updated on 2007-03-14
The URL of this page is http://www.strickling.net/orginter.htm