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| Continuing the comm port discussion... |
| TakaIsSilly - Mar 14, 2003 |
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TakaIsSilly | Mar 14, 2003 | ||
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Well, this link was interesting, so why don't i see what i can do: -- Here's... the pinout of the port, or at least I think it is. Using a serial cable should allow you to trigger remote interrupts, which is a big plus. However, I've never even seen a link cable so there's not much chance of experimenting. (The MIDI interface would also be interesting to play with.) -- If I read the schematic right, this means the Communications Port is actually plugged straight into the SCI bus of the SH-2, both master and slave... meaning it's most likely fully controllable. (I belive theres a SCI.c somewhere around the compiller) The plug it's the main problem... but there are test pads 15, 16 and 17 on that schematic that, if they're consistent between board revisions (they're on my board as well), can be soldered to an adapter or to stick the whole device inside, adding a ordinary port. The cable might be built for serial purposes with a MAX232, or, what I find more interesting, to USB if we add a TI3410 to the mix(I just requested some samples for it). Ti3410 has a RS232 conversion and 3 I/O pins and is programmable hence looks like a perfect solution. | ||||
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ExCyber | Mar 14, 2003 | ||
| Digi-Key... has them for ~$5US each, though you'll pay a "handling fee" of $5 if you don't order a bit more stuff... | ||||
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ExCyber | Mar 14, 2003 | ||
| While I won't say that's a bad idea, the controller ports are used by most software, and require configuration of the SMPC. The serial port would be more available for use. | ||||
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wonder_k | Mar 14, 2003 | ||
isn't the rumoured link-cable what we need? i mean, snip it apart and see how to attach a standard serial plug. the cable shouldn't be that problematic but since the port seems to be almost directly connected to the CPUs testing might dangerours. f.e.: voltage too high -> buzz....
 JJK! anyhow, the pinout really does help i think. shouldn't be that hard to write a SerialLoader. BTW, what's this... suppoesed to show? the CD-block? | ||||
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ExCyber | Mar 14, 2003 | ||
| Yes. I was thinking about looking for some interesting interconnections between the VCD card slot, the cartridge port, and the CD subsystem... it'll have to wait a bit though. | ||||
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TakaIsSilly | Mar 14, 2003 | ||
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lets see... wonder_k : The link cable only comes packed with a japanese BASIC package. Not only it's expensive, it's also rare enough for me to even think about trying to wreck one of those. Besides, the schematic looks pretty certain that it's the serial connections, and i'm tempted to agree with him, since each SH-2 has this very complex and enhanced serial interface it would be a waste not to use it. Add to that the 5V output and this is a perfect candidate to a serial port interface. I'm trying first the (very basic) SCI library on this page: http://www02.so-net.ne.jp/~sakura_s/hamaken/sh2/... built on those files: - sci.c - scidrv.s - Makefile - sci.h That implements : void sci_putstr(char* buff); int sci_getchar(void); If that fails, there are a couple of other options... As for the scematics, he does claim to be working on pure guess. I suppose he figured VDP1 and VDP2 were closely numbered. Remember he provably never looked at the official documentation. | ||||
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antime | Mar 14, 2003 | |||
Lik-Sang are carrying Blaze cables... for USD7.99 so it's not that expensive. No BASIC included, but you can make two interfaces from one cable. | |||||
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TakaIsSilly | Mar 15, 2003 | ||
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Done some early designs for the link cable: http://sweet.ua.pt/~a19824/en_satlink.htm... (geez, looks suspiciously like one of those cellphone cables.) I DID NOT test this cable, so I really DON'T RECOMMEND building it. That said, Im going to build it. I found out the correct SSR registers and i'm editing the files i got to conform to SH7604. | ||||
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ExCyber | Mar 15, 2003 | ||
| Cool. I've thought about combining this with a couple other enhancements if I can set up a decent place to solder... | ||||
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TakaIsSilly | Mar 15, 2003 | ||
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As both my Saturns are dead (and I just lifted a track from the mainboard of one of those, out of pure frustation, autch - nothing to do with this cable, BTW), I won't be able to test for a couple of days, so here's a tiny Saturn binary file I rigged up to test the device. This should send "Hello World!" to the comm port once after you press Start - Assincronous, 8-bit + 1 Stop, No Parity. I don't know at what speed the port is setup, provably it's some ludicrous speed if the bios hasn't init it, but at least it should give some garbish: http://sweet.ua.pt/~a19824/binary/sl.bin... | ||||
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ExCyber | Mar 16, 2003 | |||
Just managed to blow a fuse on one myself.  I might put this off for a bit; don't want to be left without a working Saturn... | |||||
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ExCyber | Mar 17, 2003 | ||
I was talking about the TUSB3410, actually.  | ||||
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TakaIsSilly | Mar 23, 2003 | ||
Been designing the interface for uploads. Will look something like this, bugs by Toss fixed   As for the cable it's pending on getting a new Saturn in the next days. | ||||
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TakaIsSilly | Mar 28, 2003 | ||
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Making some dumb work while waiting : Here's a simple interface for programming the serial port. You can use it to code for the ordinary link cable! Have them both sci_init() at the same baud rate, and data will transfer between machines. I didn't added info with the files, use the included Makefile to complie, and then move scidriver.o, sci.h and sci.o to your current program. Here's what the functions do, if they're not very explicit. void sci_init(char baud); Inits the SCI port with an asyncronous protocol. you can pick the baud rate between 1200 and 38400. void sci_putchar(char data); Sends data tru the port. void sci_putstr(char* buff); Sends a whole string of null-terminated data. int sci_getchar(void); Retrieves a byte from the port. Sorry about the int, cast it to a char or modify it yourself ^^; They're not tested on the real thing, but Satourne and GiriGiri seem to respond positively. http://sweet.ua.pt/~a19824/sources/sci.zip... | ||||
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