40-column text modes on Sharp organisers with the 16-column IQ-707 BASIC card
Wednesday, 2nd July 2025
Recent posts on here have taken a bit of a detour into Sharp Pocket Computer territory. When hunting down parts or accessories for them on eBay I'll occasionally be recommended other Sharp devices, such as their calculators or organisers, if an exact match for the thing I'm actually hunting for can't be found. Calculators are indeed a useful tool, so I appreciate those recommendations, but mid-1980s electronic organisers are not usually the sort of thing I'd be too interested in.
However, some of Sharp's organisers are definitely worth a look, and these are often considerably cheaper to pick up second-hand than pocket computers or calculators. I suspect this is partially due to difficulty in testing them and perhaps a bit of user error – they often require a large number of CR2032 cells to be installed, usually after removing a screwed-on back cover, and have a series of interlock switches that all need to be set just right before the device will even try to switch on. As a result, I've acquired quite a large collection of them for very little money, mostly sold as faulty or untested but all working just fine.
These particular organisers have a card slot on them, which can be used to expand the device's capabilities via a credit card-sized "IC card". The most common sort that you'll find is a RAM expansion card, which allows you to store more data (notes, calendar appointments, address book entries and the like) in a separate area to the device's built-in memory. More interesting, however, are the application IC cards. Dictionaries, thesauri, spreadsheets and even games were made available.
To me the most appealing is the Scientific Computer Card. The organisers do have a simple calculator built in, but the Scientific Computer Card adds more advanced calculator features such as trigonometric functions, logarithms and a statistics package. This is all handled via a very capable BASIC interpreter built into the card, and you can write your own programs on the organiser. The organisers also have a 4-pin "option" port that can be connected to a printer and cassette interface, and a 15-pin "PC link" serial port, so when you slot the card into your organiser you are in effect turning it into a pocket computer (though with all the accessories attached, you might need pretty large pockets!)
My only real criticism of this arrangement when compared to Sharp's dedicated pocket computers is the IQ-7000's keyboard. It's not too difficult to get used to the non-QWERTY alphabetic characters, but for BASIC programs you often need certain symbols (such as the speech mark, comma, semicolon, colon, less/greater than or ampersand) which are not present on the organiser's keyboard – they're only available via a pop-up menu that appears when you press the SMBL key. This menu only shows 10 options at a time and you need to hunt up and down through it to find the symbol you need; not an ideal experience!
Fortunately, Sharp released later organiser models (such as the IQ-8000) with QWERTY keyboards. Not only are these more comfortable to type on, but most of the symbols are now accessible via a shift key and these organisers retained backwards compatibility with the IC cards from the earlier IQ-7000 organisers.
The screen is also quite a bit larger and clearer, albeit now with non-square pixels which can make applications look a little skinny. Unfortunately, old applications developed with the 96×64 pixel display on the IQ-7000 in mind won't know how to take advantage of the 240×64 pixel display of the IQ-8000 and so are rendered on the left hand side of the display with a separator line. That seems like an awful lot of wasted space!
Application cards that took full advantage of the larger screens (up to 40 columns of text) were sometimes sold separately to the versions that were only designed for the smaller-screen devices (16 columns of text). For example, the above photo shows two cards of the same software – 3 Dimensional Spreadsheet for Electronic Organizer – with different card numbers (IQ-706A v IQ-8B01). The card on the right has 16/40 printed in the top right corner, showing it supports both 16-column and 40-column organisers. The card on the left doesn't, and will work in both, but will only display in the leftmost 16 columns.
As an aside, another difference is that the IQ-8B01 version has an extra "Graph" button on it. When the cards are inserted the front labels are visible through a transparent window. That window is touch-sensitive and allows cards to provide custom key shortcuts to certain functions. The graph function will work on a smaller-screen organiser though it is a little cramped; I'm not sure why it wasn't otherwise provided on the IQ-706A.
There was a 40-column version of the Scientific Computer Card available (card number IQ-8B03), however I have yet to find one come up for sale and so I've been making the most of my IQ-707. However, I did find something interesting when I used it on my IQ-8000: certain primitive drawing operations could access the whole screen, even if the rest of the application was constrained to a smaller window.
The photo on the left shows the results of drawing a line from (0, 0) to (239, 63) – the line ends up being drawn successfully outside of the 96×64 window at the left of the screen. The second photo uses the same coordinates but also appends the X (invert) and BF (box fill) options which should in theory invert the whole screen, but only ends up inverting the leftmost 96×64 pixels.
Certain other drawing operations (such as PSET and GPRINT) will also happily draw to the whole screen, but text cannot be positioned or drawn outside the 16×8 grid. At this point I wasn't sure if it was the BASIC interpreter or the organiser's OS that was to blame, but I wasn't really sure how to pick apart either of them.
One potential clue came in the form of the WIDTH statement. The IQ-7000 effectively has two screen modes, with differently-sized text characters: the default small font in a 16×8 grid and a larger font that reduces the number of displayed characters to 12×4. These modes can be switched by pressing the button marked 4↔8 Lines, or programatically via WIDTH 16,8 or WIDTH 12,4. The IQ-8000 expands these to 40×8 and 30×4, but trying WIDTH 40,8 or WIDTH 30,4 just displayed an error message. However, something, somewhere must know where the rightmost column number is to allow for proper text wrapping.
I mentioned that the BASIC interpreter is very capable, and it does have an undocumented PEEK function which allows you to read a byte from anywhere in the organiser's memory. I wrote a BASIC program that would scan through memory, switching screen modes with WIDTH and seeing if the value at the address in question changed. Once I'd done this I looked at the addresses that had values that changed in meaningful ways (e.g. between 16 and 12 or 8 and 4).
It looks like the current screen width (in characters) is held in BASIC's memory at &3F988 and the height at &3F989. POKEing a larger width into &3F988 does look like it might start working – if you type then the cursor goes off the right of the 96×64 window and can be seen blinking in the screen beyond, however no characters are printed in this area and certain operations (such as listing programs with long lines) misbehaves in strange ways. There must be more to the puzzle.
Unfortunately, without knowing more about the internal operation of the operating system or BASIC I wasn't sure where to look. However, having been able to draw lines on the full screen I contented myself with adapting a very clever program by @bazzargh that renders the Great Wave as a fractal for the device (the BASIC listing can be seen here: GREATWAV.BAS).
The next breakthrough was coming across this GitHub repository when looking for other technical reference documents. It has a scan of the "ESR-L Instruction Manual" which documents the Sharp ESR-L microprocessor. Some hand-written notes on the cover of the scan mention that it's "for the PC-E500, OZ-7000 series [and] IQ-7000 series", so should be useful for the IQ-7000 organiser. Looking up the PC-E500 led me to this repository from the same owner which has a PC-E500 reference. Even if the IQ-7000 is not the same as the PC-E500, the use of the same CPU in products from the same company made me think there may be other similarities to help understand how the IQ-7000 works. Using the PC-E500 as a search term also brought me to a page of resources on Andrew Woods' website and from there and digging around in the links (including a few trips to the Internet Archive's Wayback Machine) I was able to source a cross-assembler and disassembler.
I now felt I was in a good position to start pulling apart the BASIC interpreter and OS to figure out if it was possible to use the full screen on my IQ-8000. Of course, I'd need to have a ROM dump to inspect, and fortunately this was quite easy to pull off; after all, I already had a BASIC interpreter running on the device! A simple loop over the desired address ranges, PEEKing each byte then PRINT#ing it to the organiser's serial port with a program on my PC receiving the data and storing it in a file left me with some hefty binaries to dig into.
The size did indeed present a bit of a problem. I did have a disassembler, but not a particularly sophisticated one and feeding it the 128KB of BASIC interpreter ROM didn't provide particularly useful results. I'd normally use Ghidra for a job like this, but it doesn't know about the Sharp ESR-L CPU.
However, Ghidra is user-extensible and I did now have an instruction manual/reference for the CPU, so I did my best to learn how to describe the CPU to Ghidra. This was no small undertaking, as I didn't really know my way around the CPU yet myself. After a bit of work I put together this terrible first attempt. I do not recommend using it yourself, as I haven't fully checked that every instruction disassembles correctly and a very large number of instructions don't describe what they do (or if they do, they might do it incorrectly). The disassembly should be somewhat usable, but the decompilation is mostly useless at the moment.
I thought the title screen would be a good starting point to disassemble as I could clearly find where the strings for "BASIC Card" and the equals signs that form the border were in the binary, and from there find out where they were referenced and disassemble the instructions around those references until it made some sort of sense.
This is where the PC-E500 reference ended up being surprisingly useful, as it does share a fair amount in common with the IQ-7000. The way that both operating systems provide access to the hardware is via an IOCS routine at address &FFFE8, and the routine numbers and parameter assignments in the CPU's internal memory appear to be the same on both devices. One difference is certain locations in RAM are different (for example, the location of the text flags or the dot pattern used to draw lines) however these differences are fairly easy to identify.
If you look at the Ghidra screenshot above you'll see that the disassembly on the left looks vaguely sensible but the decompilation on the right is a right mess: for reasons I haven't yet figured out it appears to show stack operations during calls as assignments to variables on the stack (uStack000001 etc) and assignments to variables in RAM which are used as parameters to functions (e.g. BX and DX) are shown as both manual assignments and in the function call parameters.
Trusting the disassembly rather than the decompilation, I dug around in the code, trying to find something that was making use of the magic numbers relating to the screen dimensions: anything with 16, 8, 12 and 4 in close proximity would be a good candidate and I eventually found something promising:
The ESR-L is a little-endian CPU so the hex constants 0x810 and 0x40C in the following code correspond to (16, 8) and (12, 4) in memory.
050eb2 0a 10 08 MV BA,0x810 050eb5 aa 46 fd 03 MV [DAT_03fd46],BA 050eb9 0a 0c 04 MV BA,0x40c 050ebc aa 48 fd 03 MV [DAT_03fd48],BA
They're stored at &3FD46 and &3FD48 in memory, so directly adjacent to each other, and the surrounding code blocks operate on the cursor's X position and textflags, so it all seems highly relevant to what we're looking for. Those values in memory can be changed with POKE:
POKE &3FD46,40,8,30,4
The side-effect of this change is that you can now use WIDTH 40,8 and WIDTH 30,4 and the mode changes accordingly. However, when you type, text is still invisible once the cursor roams outside the leftmost 96×64 region of the screen. Clearly something else needs to change.
Further up in the code the values at &3FD46 and &3FD48 are copied from other values at &1FD9D and &01FD9F:
050e97 8a 9d fd 01 MV BA,[DAT_01fd9d] 050e9b aa 46 fd 03 MV [DAT_03fd46],BA 050e9f 8a 9f fd 01 MV BA,[DAT_01fd9f] 050ea3 aa 48 fd 03 MV [DAT_03fd48],BA
These source addresses are in the organiser's own memory rather than the memory built into the BASIC card, so it seems likely that these are the system values for width and height of the screen in the small and large fonts respectively and BASIC maintains its own copies of them which are the values we found before. We could POKE our new text resolutions into those memory locations too, which can be done with this program:
10 POKE &1FD9D,40,8,30,4 20 POKE &3FD46,40,8,30,4 30 WIDTH 40,8 40 CLS
After doing this, the whole screen becomes available to our BASIC program! All graphics operations work on the whole screen and text can be placed and displayed anywhere on it successfully:
I doubt this is the "correct" way to do it, and there is likely a proper IOCS call that updates the screen resolution. As a result there may be other system variables that are not properly updated by directly POKEing values into memory, but so far I haven't run into any significant problems. As I continue to work through the system ROM disassembly I may find the appropriate routines, however.
I did try to see if the full screen size was stored somewhere in the ROM image, as it would be useful to use this to know how to properly set the display mode according to the current organiser's capabilities. I did find the byte sequence (16, 8, 12, 4) in the IQ-7000 (&F083C) and IQ-7400 (&F478A) ROM dumps and the byte sequence (40, 8, 30, 4) in the IQ-8000 (&F1412), IQ-8200 (&F1418) and IQ-8300M (&F1423) ROM dumps. I couldn't find any code that was able to meaningfully access these sequences from a user application. There may be some way to properly identify the device you're running on but I'm not currently sure of a reliable way. One potential option is to use POINT(96,0) – this returns the status of a pixel on the display (0 for off, 1 for on), and crucially it returns -1 if the value is outside the screen bounds. On an IQ-7000 it returns -1, but on an IQ-8000 it returns 0 or 1. However, a later organiser model throws a spanner in the works…
This is the Sharp IQ-8920. Its screen is still 240 pixels wide, like the IQ-8000, but it is significantly taller and has square pixels. When I first saw one of these online I was less interested in it as it didn't have the obvious card slot, but when I looked at a closer photo of it I could see that it still had one on the side. I couldn't see how this would work, as it's missing the window to see the card's buttons through, but I ended up picking one up anyway. It turns out it is still backwards-compatible with the cards from the earlier organisers, and this backwards-compatibility is achieved by displaying the card's buttons directly on the resistive touchscreen (I assume there's a database of cards and their button assignments somewhere in the IQ-8920's ROM). The IQ-8920 also corrects one notable oversight of the IQ-8000…
Attempting to draw graphics out-of-bounds on the IQ-8920 results in them being properly clipped, unlike the IQ-8000 which permits some graphics operations to work even when only the leftmost 96×64 region of the screen should be accessible. This means that on the IQ-8920, POINT(96,0) returns -1 by default and so this can't be used to detect a device with a screen that is wider than 96 pixels.
However, the same BASIC POKE program can be used to get the IQ-8920 to use the full width of the display:
I did also try extending the height of the screen, and though this looks a little promising at the start (as you work down the screen, new lines of text start overwriting the on-screen button display) things go very wrong when the screen tries to scroll and the organiser hangs quite often. Some other scrolling operations do misbehave (e.g. when scrolling through a program listing, occasionally a single line of text may appear invisible) and I'm not entirely sure what the cause is yet. The Great Wave does at least now appear on the IQ-8920:
One thing which susprisingly does not misbehave is if you extend the screen resolution on an original IQ-7000 or IQ-7400. Text disappears off the right of the display, but I haven't seen it crash or hang the organiser. POINT(96,0) still returns -1 with the screen extended on this organiser, so one solution may be to just to try to set the screen to the higher resolution, check if POINT(96,0) is out of bounds, and if it is reset back to the lower resolution. The program would then look like this:
10 POKE &1FD9D,40,8,30,4 20 POKE &3FD46,40,8,30,4 30 WIDTH 40,8 40 CLS 50 IF POINT(96,0)=0THEN END 60 POKE &1FD9D,16,8,12,4 70 POKE &3FD46,16,8,12,4 80 WIDTH 16,8 90 CLS
I will continue to dive into the OS ROM disassemblies to see if I can find ways to make this more reliable and whether there's a more correct way to do this. It would be useful to be able to dump the ROMs for the other 16/40 cards I have to see how they manage the mode switch, however as I've been dumping the ROMs from a BASIC program and I don't have an organiser with two card slots I don't currently have a way to do that. The card lock switch (which causes the organiser to switch off and reset when changing cards) appears to be handled in software (rather than being a hardware interlock) so it may be possible to write a ROM dumping program in assembly, copy it to somewhere safe in RAM from a BASIC program and then hot-swap the cards. There's 2KB of clipboard buffer that looks usable for this process, and you can CALL machine code you've POKEd into memory – I have no idea whether that will be technically possible, though, so this is just something at a very early idea stage.
I did discover a test menu in the IQ-7000 and IQ-7400 ROMs, though. Bear in mind that accessing these will reset your organiser's settings and may clear the RAM, so don't do it on an organiser that contains data you care about!
The one in the IQ-7000 isn't particularly enlightening, but can be accessed by holding ON+9 when pressing the reset button. The one on the IQ-7400 is more interesting and can be accessed by holding ON+CALC when resetting. Of particular note here is a memory dump, which allows you to enter an address and shows the data at that address on the screen. This would allow you to dump an IC card, but it only shows 16 bytes at a time and so could be very time consuming to work through! There is also a memory save and load routine in the test menu that looks like it will transmit the data from the organiser, but unfortunately it doesn't appear to let you enter the start address or length and just exports the built-in RAM rather than letting you enter the address of a card in the slot. The IQ-7400 also has a ROM version screen that can be shown by holding ON+A when resetting.
I don't know if this will have persuaded anyone that Sharp's electronics organisers are more interesting than they might first appear, but if you can pick one up along with a Scientific Computer Card I think you'll find they're fun little devices to experiment with!