6551 vs 6850 vs 8250 vs ?

BigDumbDinosaur · Post by **BigDumbDinosaur** » Wed Oct 05, 2011 4:41 am

BillO wrote:

A USART (like a 2651 or 16550) is the big boy in low speed communications. Both the ACIA and UART have subset functionality and are essentially the same.

I'm using the NXP 2692A dual ACIA in my POC design. It has just about all of the bells and whistles of the 16550, except for a smaller FIFO. I've done loopback tests on the POC and it'll easily handle 115.2 Kbps CBAT through one port with Ø2 at 8 MHz. The 2692 also has timers and other toys with which to play. Best of all, interfacing it to the 65xx bus is no big deal.

GARTHWILSON · Post by **GARTHWILSON** » Wed Oct 05, 2011 5:03 am

Quote:

More recently I had actually wanted to find a romable Forth to put on it as well, but ran out of steam on that.

My job doesn't seem very secure because of dismal sales for the last year or two. If I get let go, one thing I want to do with my time is publish my '02 and '816 Forth kernels as assembler sources. The '816 one is closer to ready for publishing but has only collected dust for many years. My '02 Forth will need more work to make it public, especially for an all-RAM model, as the current one is ROMed. (The primary difference is how variables are compiled.)

It is a very rich Forth though, and adds full interrupt support in high-level Forth with prioritized interrupts that can be installed and deleted on the fly, more program structures than others have ready-made, date & time (including multiple alarms for carrying out tasks at assigned times, with 10ms granularity in the case of my workbench computer), trig, log, square-root, random-number, and extended-precision functions, 32-bit looping controls (in addition to the normal 16-bit ones), ability to go into assembly language in the middle of a secondary and back again, and more primitives for faster execution of words that are usually written as secondaries. It's mostly Forth-83 but has a lot of enhancements from ANS, Brodie's books "Starting Forth" and "Thinking Forth," Forth Dimensions, F-PC, common Forth usage, and my own experience. There may be a lot more there than you need, but various portions will be in INCLude files that you can leave out if you like.

ElEctric_EyE · Post by **ElEctric_EyE** » Wed Oct 05, 2011 10:32 am

GARTHWILSON wrote:

...My job doesn't seem very secure because of dismal sales for the last year or two. If I get let go, one thing I want to do with my time is publish my '02 and '816 Forth kernels as assembler sources...

Sorry to hear that Garth... Just out of curiosity, how big is your version for the 6502?

BigDumbDinosaur · Post by **BigDumbDinosaur** » Wed Oct 05, 2011 4:46 pm

GARTHWILSON wrote:

My job doesn't seem very secure because of dismal sales for the last year or two.

Let's hope that isn't the case. <Sigh>

Many of my clients are suffering from sagging sales, some of it due to the decline of the manufacturing sector of our economy. Meanwhile, our so-called leaders fiddle while the USA burns. Adding insult to injury, Obama's jobs "czar," Jeffrey Immelt, relocated key parts of GE's manufacturing operations to China. Just how is that going to improve the jobs picture?

Reagan got it right with his wisecrack about fearing anyone who says they are from the government and are there to help.

GARTHWILSON · Post by **GARTHWILSON** » Wed Oct 05, 2011 5:29 pm

Quote:

Just out of curiosity, how big is your version for the 6502?

To avoid further highjacking this topic, I put a response at viewtopic.php?p=16280#16280 .

Dajgoro · Post by **Dajgoro** » Mon Apr 02, 2012 12:12 am

Today finally i had some free time, and i went to do something i have been postponing from the beginning of my sbc project...
So i soldered the unsoldered pins, and connected the 6850 to the Cp2102 usb to tll module. At first it didn't work, i with my scope i quickly discovered that i missed a pin on the 4040 counter, and i got baud rate 4800 instead of 9600... But again it didn't work... I wend to check everything with the scope, and the usb module gave some weird results, after a few hours i discovered why. The RXD on the usb module is transmit and TXD is receive

CCC... After i switched the two wires it worked perfectly...
Now if I just could manage to get the usb module working on my android device that i got as a birthday present, that would be great...

GARTHWILSON · Post by **GARTHWILSON** » Thu Apr 05, 2012 7:43 am

I blew the dust off an RS-232 primer article I wrote 9 years ago but never did anything with, and updated some links and things and posted it on my website, at http://wilsonminesco.com/RS-232/RS-232primer.html .

BigDumbDinosaur · Post by **BigDumbDinosaur** » Thu Apr 05, 2012 3:51 pm

GARTHWILSON wrote:

I blew the dust off an RS-232 primer article I wrote 9 years ago but never did anything with, and updated some links and things and posted it on my website, at http://wilsonminesco.com/RS-232/RS-232primer.html .

<Sneezing from flying dust>

Joking aside, in the section about connectors you might want to mention the common use of RJ-45 connectors for TIA-232 connections. Both Equinox and Digiboard serial adapter units offer them along with DB-25 connectors.

GARTHWILSON · Post by **GARTHWILSON** » Thu Apr 05, 2012 7:51 pm

Quote:

Yeah, maybe I should add some outdated cartoons like my interrupts primer—maybe of the IBM men putting on their garters and singing their company songs, or women with short skirts and beehive hairdos. :lol:

Quote:

Joking aside, in the section about connectors you might want to mention the common use of RJ-45 connectors for TIA-232 connections. Both Equinox and Digiboard serial adapter units offer them along with DB-25 connectors.

An article I referenced as having more on the connectors does indeed tell about them, with good diagrams. RJ-45 is neat in that it's more compact and quicker to plug in and unplug, but I wish they had put the pins for the PC board on .100" centers so they could be inserted into standard perfboard. Of course the DB-25 is no better, and the DB-9 is still kind of bad for that, but they do seem to be more reliable for making dependable connections.

BigDumbDinosaur · Post by **BigDumbDinosaur** » Fri Apr 06, 2012 4:44 am

GARTHWILSON wrote:

Quote:

Yeah, maybe I should add some outdated cartoons like my interrupts primer-- maybe of the IBM men putting on their garters and singing their company songs, or women with short skirts and beehive hairdos.

Don't forget the punch card readers and the Tele-Type machines!

Quote:

Joking aside, in the section about connectors you might want to mention the common use of RJ-45 connectors for TIA-232 connections. Both Equinox and Digiboard serial adapter units offer them along with DB-25 connectors.

An article I referenced as having more on the connectors does indeed tell about them, with good diagrams. RJ-45 is neat in that it's more compact and quicker to plug in and unplug, but I wish they had put the pins for the PC board on .100" centers so they could be inserted into standard perfboard.

The dual RJ-45 connector I used on POC V1 has two rows of pins, with 100 mil centers between the rows. However, the pins in one row are staggered 50 mils relative to the pins in the other row. While this wouldn't pose a problem with a PCB layout, one would be forced to drill 8 small holes to work with perf board. Not real hobby friendly.

GARTHWILSON · Post by **GARTHWILSON** » Fri Apr 06, 2012 5:34 am

Quote:

Don't forget the punch card readers and the Tele-Type machines!

The first computer I used was an IBM 360, and we lowly students had to sit at the big card-punch machine desk to do the cards (which we had to buy in the college book store) and transfer our programs which we wrote by hand, one line to a card, in Fortran IV. A few years later I was working at a radio station where the news came in on a teletype machine that typed slowly on newsprint paper that came on rolls. I suspect it used EBCDIC instead of ASCII. A few years after that I was working in applications engineering at a microwave power transistor manufacturer. They didn't have a fax machine yet in this company of 350 people, but I remember seeing the highest-ranking secretary using paper tape in connection with the telex machine.

Just for fun: How much room would it take to store a 2-hour movie on paper tape?

BigEd · Post by **BigEd** » Fri Apr 06, 2012 6:12 am

Is that 3800 MByte at 10 bytes/inch? That seems to be something over 6000 miles.

(Estimates of a movie size seem to vary from 300MByte to nearly 5Gbyte - depends on quality and encoding.) And I'm assuming 8-bit wide tape, which feels wrong.

Edit to add: you can still buy equipment and supplies!

GARTHWILSON · Post by **GARTHWILSON** » Fri Apr 06, 2012 6:14 am

Commercially made DVDs, IIRC, can hold up to 25GB.

When our younger son was preparing for college a few years ago, he was looking through the requirements. One was that he have a computer. I asked him if it said the student had to be older than his/her computer.

Arlet · Post by **Arlet** » Fri Apr 06, 2012 8:06 am

BigEd wrote:

Is that 3800 MByte at 10 bytes/inch? That seems to be something over 6000 miles.

A 3000 mile/hour paper tape feeder would scare me.

BigEd · Post by **BigEd** » Fri Apr 06, 2012 9:21 am

I hadn't thought of that. You could run 100 colossus-style readers in parallel.

6551 vs 6850 vs 8250 vs ?

Sagging Sales

RJ-45 TIA-232 Connections