Help with SYM-1 BASIC

[rea5245]

Hi,

I'm confused about how to set up SYM-1 BASIC. At the SYM-1 page (http://www.6502.org/trainers/synertek/) there's a 4K ROM with BASIC at $C000, another at $D000, and an 8K ROM for $C000-DFFF.

So is it an 8K BASIC that can be installed as one 8K ROM or two 4K ROMs? Or is it a position-independent 4K BASIC that can be located either at $C000 or $D000? Or is it a position-dependent 4K BASIC that's been re-assembled so it can run at $C000 or $D000? Is the 8K BIN just holding 4K BASIC and wasting the other half of ROM? According to the manual, BASIC is a single 4K ROM that goes at $C000.

What does the BASIC extension contain? Why is it in two contiguous BINs instead of one big BIN? Is there any documentation for it?

Thank you,
Bob

[BigEd]

Hi Bob, and welcome!

It looks to me like the two 4k images are to be used together, in the case that you want to program a pair of 4k ROMs, and the 8k image is the one to use if you want to program a single 8k ROM.

If so, the manual would be wrong: it tells you to plug a ROM into U21 and to configure the jumpers suitably for U21 and U22, but doesn't mention plugging a second ROM into U22.

[BillO]

Welcome.

There were two versions of the BASIC ROMs available.

A two ROM set (part numbers 02-0019-01 and 02-0020-1). These went into sockets U21 and U22 respectively.

A single ROM (part number 02-0058 A/B). This went into socket U21.

So, yes, you can do it either way.

It's 8K and it's position dependent. It fits in from $C000 to $DFFF.

Doc (older) is attached. The doc on this site is a newer one for the 8K image on a single ROM.

[BigEd]

(Thanks Bill! OK for us to upload your scan to the archive? We can make it clear which thing is which, now we know!)

[BillO]

Certainly!

[BigEd]

Great - thanks!

[BillO]

Hmmm, been looking for some time today for any reference to the the BASIC extensions. Can't find anything. Also can't find an assembly source for the BASIC. Lee's link is understandably gone.

It's a shame when good information is lost. Do we have a mirror/archive for our library?

[BigEd]

Indeed, it's best when websites have a succession plan, or a mirror, or both. This site is now held on github, and Mike does have a succession plan.

On the topic of Basic extensions, it seems the two extension files are different.

BXT_1200 is just 1285 useful bytes, and then filled with FF. It contains the strings PERFECT MATCH!, COMPARE ERROR AT, CHECK SUM ERROR! and INVALID DELETE RANGE!

BXT_0200 is a full 4k bytes, and contains these strings:
FOUND
LOADING
SEARCHING FOR
SAVING
CALL
STIME
EDIT
PAGE
TRACE
CHAIN
EXEC
EXTENDED SYM-BASIC BY JOHN W. BROWN
COPYRIGHT (C) 1980 SATURN SOFTWARE LIMITED
PAGE

Also noteworthy, the 8k Basic has tokens but no code for the trig functions. There's an application note which invites you to type in the hex and save to tape the approx 512 extra bytes needed. See page 30 of
http://www.6502.org/trainers/synertek/m ... hnotes.pdf

Also note that there are some SYMphysis newsletters in PDF form available on Rich Cini's site:
http://www.classiccmp.org/cini/systems.htm#RWS

[BillO]

Thanks for that stuff Ed.

[rea5245]

BillO wrote:

Welcome.
A single ROM (part number 02-0058 A/B). This went into socket U21.

The manual talks about a single ROM, 02-0058A, and has you configure the jumpers for 4K. Is the manual just plain wrong?

- Bob

[BillO]

The 1981 manual shows the correct jumpers for an 8K ROM in U21. The 1978 manual shows the correct jumpers for two 4K ROMs in U21 and U22

[BigEd]

Both versions of the manual are now in the archive:
http://6502.org/trainers/synertek/

(Thanks Bill!)

[rea5245]

BillO wrote:

The 1981 manual shows the correct jumpers for an 8K ROM in U21. The 1978 manual shows the correct jumpers for two 4K ROMs in U21 and U22

Then I'm not understanding something. The 1981 BASIC manual wants jumpers B-1, C-1, F-2, G-2, K-12, and L-13 or 14. On page 4-30 of the SYM-1 manual, B-1 and F-2 are associated with a 2332 ROM (4K). So are C-1 and G-2. To configure U21 for 8K, wouldn't you need B-1 and F-4? And do we care what C and G are jumped to if we're not using U22?

According to page 4-31, K-12 puts U20 at $C800 which I don't understand if you want U21 to be at $C000. L-13 or 14 puts U22 at $D000 or $D800 which I don't understand if you want U21 to span $C000-$DFFF (the BASIC manual is pretty cavalier about that L jumper; how can they not care whether it's connected to 13 or 14?). And why doesn't pg. 4-31 have any jumpers for U21?

I'm so confused!

- Bob

[GaBuZoMeu]

Perhaps it may help you to look from a different perspective to these sockets and jumpers:

Each 24 pin socket can be used for 2/4/8 KB ROMs or EPROMs. As most of these parts have a very similar pinout you are free to place any sort of (EP)ROM in any of the sockets. There are 3 pins (p18, p21, and p20) of each socket that need to be wired either to:
- an address line (A11 if you have a 4K device, A11 and A12 for an 8K ROM)
- to +5V (e.g. the write enable pin of an EPROM or a active high chip select or Vpp)
- to one (2K) / two (4K) / four (8K) of the 14 predecoded /CS lines provided by U10, U11 LS145 decoders

Thus you have full flexibility where you wish to place what sort of (EP)ROM and the address range it covers.

There is a table on page 4-30 that shows some common solutions for various sized (EP)ROMs.


Regards,
Arne

[BillO]

I agree. According to the schematic, the BASIC manual looks wrong A12 (4) should be going to pin 21 of the chip (F).

What IC are you using? A 2764 or do you have a 2364 ROM?