Hello, * On Fri, Jan 11, 2019 at 09:57:59PM +0100 Francesco Messineo wrote: > On Fri, Jan 11, 2019 at 9:03 PM Spiro Trikaliotis > <ml-cbmhackers@trikaliotis.net> wrote: > > BTW: "Die Floppy 1570/1571" by Karsten Schramm mentions this very > > modification on pages 177, chapter 12.4 "Burst routinen auch für den > > C64". > > > > cf. https://spiro.trikaliotis.net/download/DieFloppy1571-v3.pdf, page > > 177. > > > wow... too bad it's in an unknown language to me :( With the help of google translate: 12.4 Burst routines also for the C64 The C 64 owners among you may be partially jealous of the Lucky C128 users who have enjoyed the fast bus routines. But wait, the fast bus routines are through an interface module of the type CIA 6526, and these also exist in the C64. Like the floppy at any time, even with a connected C64 in the 1570/71 operating mode, You have already learned this in chapter 12.1.9.4. Now you will know which possibilities exist in the C64 with the 1570/71. The only difference in the serial bus of the C128 to the C64 is the wiring of two cables. On the C128, the SRQ line is in addition to the CNT pin of the CIA 1 in the computer and the DATA line additionally connected to the SP pin of the CIA 1. The CNT pin corresponds to a clock line, the speed of transmission of the shift register regulates (see also Appendix B: CIA 6526). The SP pin corresponds to the output of the serial Shift register. If you take a closer look at the assignment of the USER port of the C64, you will certainly be startled at the pins 4 to 7. These pins are named CNT1, SP1, CNT2 and SP2. These are the already described pins of the two CIA 6526 and indeed in each case the clock and the transmission line for the serial shift register. In our case So you only need the two pins with the corresponding lines of the serial bus connect. Do you want to use the same CIA 6526 as in the C128, on which also the above run burst routines, so you need to pin 4 (CNT 1) from the USER port with the SRQ (service request) line of the serial bus and pin 5 (SP 1) with its DATA line connect. You will get an original C128 bus. The burst routines described above then run almost without change on the C64. Only the handling of the MMU mode register and the flag query, whether the connected floppy in FAST mode are to be removed, since the C64 does not have Operating system routines for determining the floppy mode. Regards, Spiro. -- Spiro R. Trikaliotis http://www.trikaliotis.net/Received on 2019-01-11 23:03:48
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