Stuart

The utilties for reading and writing to the card transfer raw sector data, so transferring any volumes to the card will overwrite any partition and formatting already on the card. I'll send you a PM.

I suspect there are similar books for most early micros where most of the content is identical - it's just prefixed with the Wikipedia content for that particular micro.There's certainly one for the Microtan M65 where the 4 screenfuls of Wikipedia entry are stretched out to a 110 page book. Googling "by Lambert M. Surhone" revelas some interesting articles, including <http://www.side-line.com/news_comments.php?id=46632_0_2_0_C>. Seems like we're all in the wrong business ...

Be aware though that TI BASIC can only use VDP RAM. It knows nothing about the 32K expansion. Extended BASIC can use VDP RAM for variable storage, and 24K of the 32K for program storage. The remaining 8K or the 32K is used for assembly routine storage.

It's used in the missiles being put on top of block of flats to protect to London Olympic site against hijacked planes. The TMS9900 is the official vintage CPU of the 2012 London Olympics. Only joking of course before we all get sued for mentioning "2012", "London" and "Olympics" in the same sentence without authorisation ...

This bit ... [[ It is possible to increase maximum addressable memory size to 192 KB by splitting main memory into two memory segments - 64 KB instruction segment and 64 KB data segment. ]] The 99000 family has a set of bus activity output lines which indicate exactly what the bus is doing - getting an instruction, getting a first operand, getting a second operand, writing a result, and so on. So by decoding this along with the memory address, the bus activity can be directed to different, independent banks of memory. Which must lead to some interesting things with assemblers/compilers as an instruction operand could in theory have the same address as the instruction itself - it's just retrieved from a different bank of memory.

Just connected up my old CF7, so just to add: -- With the CF7, the device *isn't* mentioned on the TI startup screen when you power on. So that isn't an indication of whether it is working or not. -- A CF card formatted on the CF7A will catalog using Disk Manager 2 if you connect the card and CF adaptor to the old CF7.

That's an original CF7. It should work OK in the TI BASIC environment, but won't work with Extended BASIC or Editor/Assembler. You need the newer CF7A or nanoPEB for that. So in practical terms it's not actually a lot of use. You shouldn't need to power the CF adaptor separetely. +5V is sent up the ribbon cable and the CF adaptor should be powered by that. I had a problem with mine however and it wasn't working, and I had to solder a strap from one of the ribbon cable connector pins across to the power connector. So not all CF adaptors are born equal perhaps.

I would think though that on the sound chip the clock is also used for the processor interface (the sound chip data manual says that a write operation to the sound chip takes (can't remember the number) clock cycles, but doesn't show the connection in any diagrams). So reducing the clock speed might result in the sound chip keeping the READY line pulled low for longer? But as writes to the sound chip are relatively infrequent compared to what's going on in the rest of the system, may be it won't be noticeable?

Hi Mark, very neat work! Regarding the audio, there is no amplification of the sound chip output within the console. I've done the same mod and simply found that by the time you turn the volume down to something sensible, the noise is pretty much inaudible. Stuart. Stuart, have a look at Theirry's web site, on the audio page. There's a description of the audio out pin on the sound chip, as follows: AUDIOOUT This pin carries the sound data to the monitor's speaker (pin 3 of the connector). It is connected to an internal analog audio amplifier. I think what Thiery means is that the audio amplifier is internal to the sound chip. All those components between the sound chip pin and the monitor output are just filtering.

Hi Mark, very neat work! Regarding the audio, there is no amplification of the sound chip output within the console. I've done the same mod and simply found that by the time you turn the volume down to something sensible, the noise is pretty much inaudible. Stuart.

There's a newer edition of the Commodore book - "Commodore - a company on the edge" that's new for only $18. I bought this on Mark's recommendation and yes, it's a gret book. Another great read is "Inside Intel" by Tim Jackson. Charts the history of Intel from the very beginning.

Exactly what I meant Mark. Stuart.

Maybe your 'small talk' could include an 'interview' with a console about how it feels to be still running after all these years, using the TEII text-to-speech? Has anyone tried an "Eliza" program (http://en.wikipedia.org/wiki/ELIZA) with the text-to-speech?

Trivia: Some stack support was added to the TMS99000 (with an extra '0' ) family in the form of two instructions: BLSK - Branch immediate and push link to stack. Opcode 0000 0000 1011 XXXX 1st word of instruction is opcode + register number 2nd word of instruction is immediate operand (IOP) Function: (W) - 2 --> (W) (PC) + 4 --> (W) IOP --> (PC) So the stack pointer is in a register and the stack fills from the top downwards? BIND - Branch indirect Opcode 0000 0001 01XX XXXX 1st word of instruction is opcode +Ts + S fields Function: (SA) --> (PC) "The BIND instruction serves as the inverse of a BLSK instruction if the register indirect autoincrementing addressing mode is used." S.

I've set up a new web page for a breadboard system for a TMS 99110 processor that someone kindly gave me. The 99110 is a third-generation member of the 9900 family, and includes a macrostore feature that contains floating point instructions as part of the machine language instruction set. The processor runs at up to 6 MHz. <http://www.avjd51.dsl.pipex.com/tms99110_breadboard/tms99110_breadboard.htm> I've included some very non-scientific benchmarks of the performance of the 99110 against the 9900 and 9995 in various configurations. Even at the same clock speeds, its significantly faster. Stuart.

It's there to minimise issues with electromagnetic interference, so if you suddenly can't hear your radio any longer, you know why. The computer itself will probably work just as good. No adverse effects here - planes still safely in the sky, satellites still orbiting, and no nuclear subs washed up on the beach Although that nice new shiny nuclear sub did run aground on a sand bank quite near you (geographically speaking) ...? IIRC the tin shielding wasn't fitted at all on the QI boards, although they might have sprayed the inside of the case with shielding paint?

Note that there are at least two versions of the PAL modulator box, and some of them don't have the ASTEC modulator shown in the modification - the modulator section is constructed from separate components on the main modulator PCB.

Snap!

If you download the file ... <http://www.avjd51.dsl.pipex.com/ti/disk_images/Miscellaneous.zip> ... and extract the disk file <Miscellaneous.tidisk> from it, that contains the commented assembler source file <CART_RAM/S> for a little application to save the MiniMem RAM to disk, and to restore it again.

Might it just be easier to get a 32K card for the PEB? They're not exactly rare, plus you get half your desk space back ... Or fit 16-bit 32K in the console if you have the soldering skills. Stuart.

Yes, but you'll need the version of the CF7 which doesn't have the 32K on-board. Or be inventive and mod your CF7 to disable the 32K chip.

If you're working on the 99/4A, there are two unused pins on the 9901 that you could program as outputs, and I believe that reading these pins will return the last data output. (Need to ensure that you write to the pins before reading from them in order to program them as outputs). There are another couple of pins you could use as flags but as these control the keyboard scanning and tape operation, you could only use them if not using the keyboard/tape, and you'd have to ensure that the console code did not change them when you're not looking. The TMS9995 processor has an internal CRU flag register with 11 bits available for user-defined application. There is no internal CRU memory in the 9900 in the /4A. You could of course use a bitmask with CPU memory to store 16 flags per word, but that would obviously require more instructions, and your example seems to have a-need-for-speed ... Stuart.

There's also the port of the 9995-based Powertran Cortex BASIC I done for the TI - <http://www.avjd51.dsl.pipex.com/ti/ti.htm#programs>. Pure assembly, access to text and bitmaps modes on the VDP. Unfortunately due to the size of the code, user programs are limited to around 5K or so which makes it of little practical use. It's significantly faster than TI BASIC and Extended BASIC. You might want to try it against the Atari BASIC and see how it shapes up. Stuart.

Power. A few of the ICs require the -5V supply to be applied before the +5V and +12V. There shouldn't be a problem running the board from a different PSU as long as this is observed. [iIRC if you don't apply power in the right order then it can cause damage in the long term; it is unlikely to zap the board immediately. But don't quote me.] CF7. Just insert the card and use CALL FORMAT to format the volumes. Note that not all cards will work with the unit - but you'll lose nothing by trying. Stuart.

Are you letting the viewer + image data source code out Tursi? I'll try it on my TM990 VDP card connected to a PC TV tuner card, but I'll need to alter the 9918 read/write/status hardware addresses ...