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Question about calls from BASIC


marc.hull
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I have spent some time building and redesigning the Forti card so that I could #1 get it to play through the TI speakers with out affecting the console sound chip and adding an EPROM for a DSR. I am confident the hardware works as I can control the sound chips through easy bug and the power up routine on EPROM is doing what I expect it to do. The next step is to write some routines accessible from BASIC. I have scanned TN's pages and everything seems pretty straight forward. Just build a standard header with the info it needs and write the routines. I'm not getting much love though (except from the power up routine.) When I try to call the routines from BASIC (ie CALL FTON) I can see the LED on the card flash like the scanning routine is searching the card but then I get a not found error. I think my header is built correctly and before I go and pull my hair out looking through code that may be good I need to know if my underlying assumptions are correct.

 

If I have a routine that is named FTON that is resident on the card ROM then in order to access it I can simply type CALL FTON ? It believe that this is correct as the LED for the card and therefor the ROM flickers when I do this but I have also seen cards that access subroutine by using the DELETE command (as in file access.) DELETE FTON only gives me a syntax error. So does anyone know which method (or both) are correct for accessing subprograms in >4000 ROM ? Does this behavior change from BASIC to XBASIC ? Is there something I am missing or do I need to revisit my header ?

 

While on the DSR bandwagon I have another request. Writing a DSR on the TI is currently a pain in the ass. I have to assemble with a listing and hex edit a PC file to create an EPROM binary using the print out. SSAVE chokes on converting code to the >6000 space (with a SS cart) and I'd hate to see what would happen even with memory in the >4000 space. Is there an EA3 to EA5 converter that does not have to operate from memory (ie convert a disk based tagged code to a memory image without first loading the tagged code ?)

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I think the flashing of the LED on the card could be a red-herring. It's not flashing because your FTON routine is *executing*. It's flashing because the console is paging each CRU device in one at a time to look for a routine called FTON.

 

As far as I know, your assumption about being able to use CALL to access a routine in the DSR is correct. I'm suspecting your DSR header. You could try paging in a known good DSR (e.g. the TI Disk Controller) and examining the memory in the DSR space to double check the format of the header(s).

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That's what I am suspecting as well. I'm just trying to verify I'm not barking up the wrong tree.

 

Read the rest of the DSR specs and it looks like passing from BASIC is a real PITA. I'll have to spend some time. I'm definitely going to revisit the design to add some RAM. That should make programming a bit easier.

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