rs232 hex inverter
in [Commodore]
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From: Markco on 14 Feb 2007 00:54 Yes, I am going to socket the chip. That way if I need to replace with a standard 7404 I can just pull it without sacrificing work. I am about half way through hacking the unit into an old 300 baud Commie modem case. I desolderd all the original components and am going to put in a socketed 74s04 on the now bare pcb. I've got a ribbon cabled 9 pin connector to run out the back. and I'll run the connections to the existing user port connector on the pcb. Hopefully the 74s04 will tolerate the 5v. If not I'll have to pay the buck thirty for one from Digikey. Cheap B*****d that I am. ;-) "Clockmeister" <whowhere(a)andwhy.com> wrote in message news:12t42u3i9394139(a)corp.supernews.com... > > "Markco" <onthfly1(a)hotmail.com> wrote in message > news:xGQzh.56$On7.55(a)newsfe04.lga... >> Does anyone happen to know if a 74LS04N hex inverter can be used as a >> substitute for a 7404N ? I looked at the data sheets and the pinouts are >> the same for both chips. However some of the internals for the inverter >> circuits are set up a little differently. I'm thinking about putting >> together a simple rs232 interface for the C64 userport and wanted to know >> if I would run into problems if I used the other chip as a substitute. >> > > All should work fine in that application. A good idea would be to socket > the chip though, just in case. > > >
From: Peter Schepers on 14 Feb 2007 08:28 In article <7uxAh.1308$%C3.1156(a)newsfe02.lga>, Markco <onthfly1(a)hotmail.com> wrote: >Yes, I am going to socket the chip. That way if I need to replace with a >standard 7404 I can just pull it without sacrificing work. I am about half >way through hacking the unit into an old 300 baud Commie modem case. I >desolderd all the original components and am going to put in a socketed >74s04 on the now bare pcb. I've got a ribbon cabled 9 pin connector to run >out the back. and I'll run the connections to the existing user port >connector on the pcb. Hopefully the 74s04 will tolerate the 5v. If not I'll >have to pay the buck thirty for one from Digikey. Cheap B*****d that I am. All of the chips variations mentioned so far, LS (Low power Schottky), HCT (Highspeed Cmos Ttl-equivalent switching) & S (Schottky clamped) are all rated for 5 volts and are mostly interchangeable, especially on the slower C64. The 74xx series are all 5V rated, it's the CMOS types which are variable drive voltage, generally from 3-18V. Check out this link for more info on chip types: http://groups.google.hn/group/sci.electronics.basics/tree/browse_frm/month/2003-05/5e2a9fb8ba4f5766?rnum=241&_done=%2Fgroup%2Fsci.electronics.basics%2Fbrowse_frm%2Fmonth%2F2003-05%3F If the link is too big, here's what it says: 'F' is a Shottyky clamped FAST part. These are quite like 'AS' parts and use *lots* of power and have some fairly large dI/dt issues. 'HC' is high-speed CMOS. Generally preferred. Lower power than 'F' or 'AS', though IIRC somewhat lower performance. 'HCT' is the same has HC, but has an asymmetrical input to look like TTL. That is, the threshold is ~1.4V (TTL) rather than 2.5V (CMOS). 'AS' is advanced Schottky (like 'F' above) 'ALS' is advanced low-power Schottky ('AS' on a power diet) 'S' is Shottky clamped. ...obsoleted by 'ALS' 'LS' is low-power Schottky clamped. ...also obsoleted by 'ALS'. 'H' high-power. Obsoleleted by 'S' 'C' is CMOS. Pretty much obsoleted by 'HC'. --------------------------------------------------------------------------- Peter Schepers, | Author of : 64COPY, The C64 EMU file converter Info Systems & Technology | http://www.64copy.com University of Waterloo, | My opinion is not likely that of the Waterloo, Ontario, Canada | University, its employees, or anybody (519) 888-4567 ext 36347 | on this planet. Too bad!
From: Markco on 14 Feb 2007 13:16
I was looking at the data sheets, and the 7404 series was grouped together. Some varieties have an onboard buffer, but I stayed away from them. Thanks Peter for the reassurance. :-) This was just going to be a minor distraction from a DTV hack I am doing that I needed a break from, but it has turned out to be a project of it's own. Go figure. 8-) Unemployment has done wonders for my C64 hacking skills. Wayyyyy too much time. "Peter Schepers" <schepers(a)ist.uwaterloo.ca> wrote in message news:eqv2pf$ut9$1(a)rumours.uwaterloo.ca... > In article <7uxAh.1308$%C3.1156(a)newsfe02.lga>, > Markco <onthfly1(a)hotmail.com> wrote: >>Yes, I am going to socket the chip. That way if I need to replace with a >>standard 7404 I can just pull it without sacrificing work. I am about half >>way through hacking the unit into an old 300 baud Commie modem case. I >>desolderd all the original components and am going to put in a socketed >>74s04 on the now bare pcb. I've got a ribbon cabled 9 pin connector to run >>out the back. and I'll run the connections to the existing user port >>connector on the pcb. Hopefully the 74s04 will tolerate the 5v. If not >>I'll >>have to pay the buck thirty for one from Digikey. Cheap B*****d that I am. > > All of the chips variations mentioned so far, LS (Low power Schottky), HCT > (Highspeed Cmos Ttl-equivalent switching) & S (Schottky clamped) are all > rated for 5 volts and are mostly interchangeable, especially on the slower > C64. The 74xx series are all 5V rated, it's the CMOS types which are > variable drive voltage, generally from 3-18V. > > Check out this link for more info on chip types: > > http://groups.google.hn/group/sci.electronics.basics/tree/browse_frm/month/2003-05/5e2a9fb8ba4f5766?rnum=241&_done=%2Fgroup%2Fsci.electronics.basics%2Fbrowse_frm%2Fmonth%2F2003-05%3F > > If the link is too big, here's what it says: > > 'F' is a Shottyky clamped FAST part. These are quite like 'AS' parts and > use *lots* of power and have some fairly large dI/dt issues. > > 'HC' is high-speed CMOS. Generally preferred. Lower power than 'F' or > 'AS', though IIRC somewhat lower performance. > > 'HCT' is the same has HC, but has an asymmetrical input to look like TTL. > That is, the threshold is ~1.4V (TTL) rather than 2.5V (CMOS). > > 'AS' is advanced Schottky (like 'F' above) > > 'ALS' is advanced low-power Schottky ('AS' on a power diet) > > 'S' is Shottky clamped. ...obsoleted by 'ALS' > > 'LS' is low-power Schottky clamped. ...also obsoleted by 'ALS'. > > 'H' high-power. Obsoleleted by 'S' > > 'C' is CMOS. Pretty much obsoleted by 'HC'. > > --------------------------------------------------------------------------- > Peter Schepers, | Author of : 64COPY, The C64 EMU file converter > Info Systems & Technology | http://www.64copy.com > University of Waterloo, | My opinion is not likely that of the > Waterloo, Ontario, Canada | University, its employees, or anybody > (519) 888-4567 ext 36347 | on this planet. Too bad! > |