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That looks right, yeah. And bitswap is a MAME utility thing, it's not something you'd know generally from C++ :-)

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That got me thinking, I was using this routine to get a range of bits:

uint32_t BITS(uint32_t x, u8 m, u8 n) {return ( ((x) >> (n)) & ( ((uint32_t) 1 << ((m) - (n) + 1)) - 1));}

but I see now that if you use BIT(T x, U n, V w) from src/lib/util/coretmpl.h

so I can change:

/*
m_silentype_printer->update_cr_stepper(BITS(m_parallel_reg, 3, 0));
m_silentype_printer->update_pf_stepper(BITS(m_parallel_reg, 7, 4));
m_silentype_printer->update_printhead (BITS(m_parallel_reg, 15, 9));
*/

into this:

m_silentype_printer->update_cr_stepper(BIT(m_parallel_reg, 0, 4));
m_silentype_printer->update_pf_stepper(BIT(m_parallel_reg, 4, 4));
m_silentype_printer->update_printhead (BIT(m_parallel_reg, 9, 7));


"I did not know that." 8-)

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Rob Justice emailed me mostly complete support for two 68008 cards for the Apple II, and here's CP/M-68K running after I cleaned things up a bit.

[Linked Image from rbelmont.mameworld.info]

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Recently I found an ImageWriter dump and also found a schematic. I've been looking for those for a long time.


One thing which puzzled me was exactly how the address decoding worked, so why not model it in Logisim?

It uses a 74155 piped into a 74156 and once modeled it gives the expected results:

Logisim is cool, I just learned how to do splitters.

[Linked Image from i.imgur.com]

Modeling the 74155
[Linked Image from i.imgur.com]

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That's *really* cool. Looks like original Logisim suspended development in 2011, but it's GPL so it got picked up by a new team under the Github logisim-evolution repo. The latest version lets you define new chips in VHDL, which is super cool.

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After studying the schematics and datasheets for awhile, I was able to get the imagewriter to do its self test.

It's not quite right and a little hacky, but I'm happy to get something working.

[Linked Image from i.imgur.com]

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That's faster progress than I was expecting, even if it's got some issues still. Really cool!

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Thanks, RB!

If I pay attention to the transitions of PB7 going from 0 to 1 making the print head fire, it looks much better.

[Linked Image from i.imgur.com]

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Yup, that looks like an ImageWriter now smile

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I decided to just hardcode a timer to for 9600 baud because I haven't quite got the counters completely figured out.

And after much fiddling...

[Linked Image from i.imgur.com]

The flow control isn't quite right, so it will drop characters while printing in zoom grafix, but if I set the line delay long enough it will print.

[Linked Image from i.imgur.com]

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