Recommended Posts

So I'm experimenting with a SN54293 (datasheet: http://www.ti.com/litv/pdf/sdls097)

and I've came into a problem... I've got 2 chips, both salvaged from an old CCTV controller board.

I've tried using them with an astable 555 timer and a 74122 trigger system and it is REALLY sporatic when it works, rarely if I connect the power to it (4*AA batteries) it will work, most time it counts strangely, and doesn't use the 3rd or 4th bit (I'm driving LEDs) most the time too.

So I'm not really sure if I'm doing something wrong or what, not much point in posting a picture of the circuit (it's messy on breadboard) but basically pins 1, 2, 3, 6, 12 are unconnected, pins 4, 5, 8, 9 go to LEDs, pin 9 also goes to pin 11, pin 7, 13 go to ground and pin 14 goes to power and pin 10 goes to the 555 output or 74122 output.

Anyone got any idea why this is happening? I know TI shows the SN54293 as being obsolete but they've also got it in their current Z revision of logic devices :s

Link to comment
https://www.neowin.net/forum/topic/1123788-darn-4-bit-counter/
Share on other sites

Bah, solved. Can't believe how lax they were when this chip was designed, no considerations taken into account for what the chip would be driving, need to use 4 transistors, one for each output, so it can drive the LED otherwise if adversely affects the chips function and completely messes it up, fair enough I should have RTFM a bit closer but that is just an awful design, and to only output 8mA per output... Can see why this chip is marked as obsolete!

Anyway if anyone else encounters the same problem I hope this advice helps you :)

This topic is now closed to further replies.
  • Posts

    • I am not a fan of haptic feedback touchpads. I've owned a Surface Laptop 7 (Snapdragon) with one and a Lenovo Slim (Intel), and I hated both to the point where I purchased different laptops. It's not that they don't work most of the time; it's that they don't work 100% of the time, and there is no advantage from a user's perspective over a good mechanical trackpad like what's on a ThinkPad X1 or a Yoga 9i. I do not believe that I'll buy another haptic feedback touchpad laptop again in the near future.
    • Works fine here too. About this build, I don't like to download any kind of Windows, from any site except Microsoft. The mod might work, but I don't know what it's inside. Can contain malware, backdoors... Long time ago I've used something like this but reversed - it was 98se with the look and some functionality  of XP. Or, later XP with Vista look. But I made it myself. Not downloaded from obscure sites.
    • Rockstar gives last-gen GTA V players free upgrades tomorrow by Pulasthi Ariyasinghe Rockstar is preparing to launch Grand Theft Auto VI later this year, but ahead of that, the company has revealed a new offer for some Grand Theft Auto V owners. It today announced that Xbox One and PlayStation 4 version owners of the 2013-released title will soon be receiving a free upgrade to the current generation version. The studio released the Xbox Series X|S and PlayStation 5 version of Grand Theft Auto V back in 2022, bringing significant upgrades to the original console editions. This included 60 FPS gameplay at up to 4K resolution, as well as major upgrades to textures, draw distance, and audio. Faster load times, ray tracing elements, and HDR support were also added with it. While this new and enhanced version needed a new purchase of the game to jump in, now Rockstar has decided to make it a free upgrade, dropping the $40 price tag entirely on consoles. "Beginning tomorrow, those who own any PS4 version or the digital Xbox One version of Grand Theft Auto V will be able to upgrade to the PS5 or Xbox Series X|S versions at no additional cost, and experience the best versions of GTA V and GTA Online," said the company in an official blog post. The free upgrade offer will be released tomorrow, June 18, for all Xbox One and PlayStation 4 owners of Grand Theft Auto V. Players who will be jumping in on the offer will want to check how to migrate their GTA Online profile from last-generation to current-generation consoles by heading over here. The offer lands ahead of The Kortz Center Heist hitting Grand Theft Auto Online, where players and crews will be tasked with stealing priceless international art from a prestigious gallery in Pacific Bluffs. It doesn't look like Rockstar plans to stop updating its previous game even with Grand Theft Auto VI being on the horizon. The latest title is slated to launch on November 19, 2026, across Xbox Series X|S and PlayStation 5.
    • Now comes with a money back guarantee instead of a replacement! Hah
  • Recent Achievements

    • One Month Later
      Vincian earned a badge
      One Month Later
    • First Post
      Jocimo earned a badge
      First Post
    • Week One Done
      suprememobiles48 earned a badge
      Week One Done
    • One Month Later
      Windows Guy earned a badge
      One Month Later
    • One Month Later
      Prasann earned a badge
      One Month Later
  • Popular Contributors

    1. 1
      +primortal
      510
    2. 2
      +Edouard
      172
    3. 3
      PsYcHoKiLLa
      89
    4. 4
      Steven P.
      76
    5. 5
      neufuse
      69
  • Tell a friend

    Love Neowin? Tell a friend!