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by Nasta
Sat Aug 19, 2017 9:10 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

Re: 8302 pinout help request...

Jan, You seem to have studied that code quite a lot - would it be possible for you to write a small expanation on the 8302 internal registers and their use? Interesting that the same serial hardware is used for MDV, this would open some interesting possibilities but as far as I know it's half duplex...
by Nasta
Sat Jul 22, 2017 11:40 pm
Forum: Hardware
Topic: Issue 8 and WiFi
Replies: 37
Views: 2235

Re: Issue 8 and WiFi

How about let's compare apples to apples... The Q40 has a CPU that is almost two orders of magnitude faster than the original 68008, and, more importantly, large caches. This makes interrupt response quite fast. This fact was used on Q40 to drive various devices, originally sound, where interrupts o...
by Nasta
Fri Jul 07, 2017 1:22 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

Re: 8302 pinout help request...

Though, collisions could be detected on any bit considering that it happens when the transmitted and received bit is not the same (the system is high-dominant, a high on the line from any transmitter over-rides the low state).
by Nasta
Thu Jul 06, 2017 9:28 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

Re: 8302 pinout help request...

No, the network is a simple 'bit banging' port. Actually, you can use the same bit (7 of PC.TCTRL) to bit-bang the serial output line in software, which was used in the Qterm software supplied with the Miracle modem to achieve 1200/75 split baud rate (this was the 1200S75 mode). An explanation in t...
by Nasta
Thu Jul 06, 2017 9:19 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

Re: 8302 pinout help request...

000 = 19200 001 = 9600 010 = 4800 011 = 2400 100 = 1200 101 = 600 110 = 300 111 = 150 ??? = 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 div...
by Nasta
Wed Jul 05, 2017 1:10 am
Forum: Hardware
Topic: RE: brand new Sinclair QL
Replies: 4
Views: 444

Re: RE: brand new Sinclair QL

Simon, it is very difficult to understand some of your writing without interpunction. As Dave said - and try scrolling the screen :/ BTW just as a reference - the QL can address up to half a gigabyte of memory TOTAL (this includes all RAM, ROM, IO...) if it wants to stay compatible with most of the ...
by Nasta
Wed Jul 05, 2017 1:08 am
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

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 Q...
by Nasta
Mon Jul 03, 2017 4:32 pm
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

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...
by Nasta
Sat Jul 01, 2017 12:52 am
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

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) i...
by Nasta
Thu Jun 29, 2017 1:34 am
Forum: Hardware
Topic: 8302 pinout help request...
Replies: 26
Views: 1552

Re: 8302 pinout help request...

Yes, checked - BAUDX4 is an input to the 8049 timer input pin.
I wonder if it's actually a constant frequency (baud rate base frequency) or actually chosen baud rate x4...

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