From mailer.acns.fsu.edu!usenet.ufl.edu!usenet.fiu.edu!MathWorks.Com!europa.eng.gtefsd.com!howland.reston.ans.net!EU.net!sunic!seunet!seunet!cindy!straight!bertil.jagard Tue Jul 12 23:31:40 1994 Path: mailer.acns.fsu.edu!usenet.ufl.edu!usenet.fiu.edu!MathWorks.Com!europa.eng.gtefsd.com!howland.reston.ans.net!EU.net!sunic!seunet!seunet!cindy!straight!bertil.jagard From: bertil.jagard@straight.ct.se (Bertil Jagard) Newsgroups: comp.sys.atari.st.tech Subject: Re: Four questions: ProTr Message-ID: <211d9200@straight.ct.se> Date: Mon, 11 Jul 94 11:21:00 +0200 Sender: news@straight.ct.se Reply-To: bertil.jagard@straight.ct.se X-Newsreader: Blue Wave/QWK v2.12 [JetMail 0.99beta8] X-Mailer: uugate 0.34 (OS/2 2.10) (Fidonet Gateway) Organization: Ettans Snus ... no substitute. Lines: 191 In a Message of <07-10-94 07:12> Paulseniura writes: Pa> A third question for the people who might know: I'm *very* adept in Pa> doing circuit upgrades (practically rebuilt & redesigned my CoCo3 Pa> system, see). So I'd like to do the "38400-bps" upgrade which Pa> consists of a single 74LS74 chip wired to the MFP. The IMG drawing & Pa> doc was written by Jurgen Meyer & can be found at the Atari FTP Pa> archive sites. Only part of the doc was translated to English. I've Pa> got a 74F74 & switch ready to go if someone could tell me how it's Pa> working for you, and what-all does it really affect, etc. Try this modyfication by Flemming B. Nielsen on the MFP.. It's works perfect and you can controll it so you can shift to the original speed with a program.. Msg #8 / 1-18 Time: 24 Jun 94 00:56:24 From: Flemming B. Nielsen To : All Subj: High Speed Mod ect. ---------[N.ST.FAX]----------------------------------------------- This text is for those of you who want a high speed serial port (38400) on a standard ST(E) and still want to use their modem as a fax reciever. It all started when I decided to do the standard CD4040 modification to my MFP chip to lock the port at 38400. Allready at this early stage I encountered my first problem - I didn't have a 4040 and neither did anybody else in my town. Well I used to do a lot of electonics, so I tried to find a substitute. All it needed to do was divide by 4, so I settled for a 74LS93 of which I had plenty. I quickly put my modified modification (wow, what a mod ) together and it worked like a dream. That is until I tried sending a fax to BT-FAX. +FCON came through without any problems and BT-FAX started, but then it just stopped dead and did nothing. After several tests I came to the conclusion that the fax reciever part of the modem can't handle 38400, but has to be locked at 19200 for the fax-transmission to work. Ok, I know that there are some good german mods with several high speeds, but you had to pay for them - and I would rather build it myself if I could. I ended with a cross between several mods and here is how it works: I used a 74LS157 as switch between the standard MFP clock (just as the ST was built) and my 38400 mod. The switch is toggled by an unused RTS signal from the MIDI ACIA (something like TURBORS). When the computer is switched on it defaults to 38400. When a fax comes in I call a program of my own that takes the name of the 'real' program I want (BT-FAX) plus its command line as a combined command line. My program switches the baud rate to standard MFP (should be set at 19200) and calls BT-FAX. When BT-FAX is done my program reenables the high-speed mod. It works just as it should - and its cheap. ==================================================================== Here are the schematics: All you need is a 74LS93 and a 74LS157 + some soldering skills! You need to cut pin 16 on the MFP away from the circuit board. MFP (68901) 74LS93 74LS157 MIDI ACIA xxxxxxxxx xxxxxxxxxxxxx xxxxxxxxxxxxx xxxxxxxxxxxx 18 x-------x 1 8 x-------x 2 1 x-------x 5 x x x x x x x x x x 2 x---+ x x xxxxxxxxxxxx x x x | x x x x 3 x---+---x 15 x x x x | x x x +--x 5 10 x---+---x 8 x x | xxxxxxxxxxxxx | x x x | | x x x VCC GND x x x x x x x x 16 x---------------------------x 3 x x x x 10 x---+-----------------------x 4 x x | x x 7 x---+ x 16 x---VCC xxxxxxxxx xxxxxxxxxxxxx In a 1040ST(E) the Midi ACIA is on the right side of the PCB and it is the one towards the back. ==================================================================== And here is my software (Lattice C 5.5) /****************************************************/ /* set19200.ttp (c)1994 by Digisoft-Denmark */ /****************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #define ACIA_MIDI *(char *)(0xFFFFFC04) #define TIMER_D 0xD5 #define BAUD38400 0x95 void set_baud_clk(int); int main(int argc, char *argv[]) { int retcode; set_baud_clk(TIMER_D); /* enable TIMER_D */ argv[argc+1]=NULL; /* prepare for forkv() */ forkv(argv[1],argv+2); /* call the prog on the commandline */ /* + its parameters */ retcode=wait(); /* get its exit code */ set_baud_clk(BAUD38400); /* reenable 38400 */ return(retcode); /* return with the exit code */ } void set_baud_clk(int clk) { long OldSSP=Super(NULL); /* enter SuperViser mode */ ACIA_MIDI=clk; /* set MIDI RTS */ Super((void *)OldSSP); /* exit SuperViser mode */ } =============================================================== In Semper I have 'SET19200.TTP' as the program and 'BT_FAX.TOS -pM:\ -m -g' as the command line. Note! BT_FAX.TOS & SET19200.TTP should both be in the mailer folder. ***************************************************************** * DON'T atempt this modification if you don't understand it. * * I take absolutly NO responsibility whatsoever for anything * * that might happen because of this modification. * * It works in my STE and no doubt somebody can improve on it. * ***************************************************************** ***************************************************************** * This text and the ideas shown in it are copyright by me. * * You are allowed to use it for whatever you wish as long as * * it is credited to me and understood that I take no * * responsibility for anything that may happen. * ***************************************************************** Flemming B. Nielsen (Digisoft Denmark) 90:15/0@NeST ================================================================== Addendum!!! ================================================================== A new little problem arised. Semper will not send a EMSI handshake if Sempers portspeed is not set a 38400 and you get a connect over 19200. If you use HSMODEM and install the RSVE cookie, the data works fine; BUT as SEMPER set the speed to 38400 and using HDMODEM the MFP speed is actualy set at 110 baud - way to low for the fax. There ar 2 solutions. 1) connect pin 11 from 74LS93 to pin 3 on 74LS157. Don't connect pin 16 on the MFP to pin 3 on the 74LS157. Now it will only switch between 19200 and 38400. 2) change HSMODEM to understand my modification or at least install a new vector for RSCONF that understands my modification. Regards Bertil Jagard SysOp Swedish Atari Club.. ================================================================= = E-Mail: bertil.jagard@straight.ct.se STraight BBS, Sweden = = Phone : +46-(0)31-363973. FidoNet 2:203/221, NeST 90:1101/104 = =================================================================