Search found 140 matches

by janbredenbeek
Sat Jul 15, 2017 10:37 pm
Forum: Help for New Users
Topic: QL Tinkering
Replies: 24
Views: 2420

Re: QL Tinkering

It seems there are lines missing near the end of the program. Here are a few lines: 668 END DEFine EFine 5650 IF astro(n,3)=0 5660 ch=16:INK#ch,2:PRINT#ch,astro$(n);' Falls' 5670 IF side(Gp1,3)<30:side(Gp1,3)=side(Gp1,3)+10 5680 IF side(Gp1,3)<60:side(Gp1,3)=side(Gp1,3)+5 5690 astro(n,5)=Gp1:GO TO 5...
by janbredenbeek
Fri Jul 07, 2017 10:22 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

Dave wrote:If that is using the same hardware in the ULA, why is the QL serial port so terrible?

IMHO the transmit side is OK but the receive side (handled by the 8049) is terrible.

Jan.
by janbredenbeek
Thu Jul 06, 2017 11:11 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

Interesting, I was under the impression the net port was a real shift register and only the various protocol timings were implemented in software. I stand corrected :) The good old Sinclair adagium: "Never do it in hardware if it can be done in software" :D On the other hand, the network ...
by janbredenbeek
Thu Jul 06, 2017 10:52 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

110 = 300 111 = 150 ??? = 75? 150 baud doesn't exist. It jumps from 300 to 75. Also, it probably can't go much faster without a serious baud rate error accruing. If it uses a 4x oversample for baud rate (visible at BAUDX4), and the base is the 7.5MHZ clock, ideally for 19200 the divisor would be 97...
by janbredenbeek
Wed Jul 05, 2017 11:56 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

Do you happen to know the baud rates indicated by the three bits? These are the standard QL baud rates in reverse order. 000 = 19200, 001 = 9600 etc, down to 75 for 111. The 8302 can probably go much faster than that since it has to drive the Microdrives using the same shift register (controlled by...
by janbredenbeek
Wed Jul 05, 2017 2:55 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

That means Minerva might well change the baud rate field in the register as it services interrupts for serial transmit, to get different baud rates. To be honest, this looks like one more reason to keep one non-multiplexed serial port. Do you perhaps know if the same shift register is used for the ...
by janbredenbeek
Mon Jul 03, 2017 11:21 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

Jan, are you sure the 8302 serial transmit has independent baud rates for the two outputs? I'm not sure they can actually really transmit at the same time... They never transmit both at the same time, there is always interleave between bytes (there's probably only one shift register which might als...
by janbredenbeek
Sat Jul 01, 2017 12:43 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

That reminded me - I seem to remember Hermes does not use BAUDX4. The trick is, the 11MHz clock is close enough (0.6%) to the standard 11.0592 standard baud rate generator crystal (Sinclair must have had loads of 11MHz since this, unlike the 11.0592 is not standard and usually MUCH more expensive) ...
by janbredenbeek
Sat Jul 01, 2017 12:07 am
Forum: Hardware
Topic: What features matter to you?
Replies: 18
Views: 1131

Re: What features matter to you?

So, microdrives and UHF output would be GONE . Serial and RGB are SAFE . Does that include composite video? I can live without UHF but my PC's TV card which I use as monitor has only composite input (Y/C to be exact which is somewhat better - only need to find a way to catch the C signal from the M...
by janbredenbeek
Fri Jun 30, 2017 11:40 am
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 24
Views: 1322

Re: 8302 pinout help request...

After making a trip down memory lane I can indeed confirm that the 8302 generates a true BAUDX4 signal. I even used it back in 1987 to drive my own serial port using a 6850 ACIA. I took the signal from pin 5 and set the BAUD rate to 4800 in order to drive my dumb 1200/75 baud modem, thus avoiding th...

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