ozfalcon Posted October 26, 2014 Share Posted October 26, 2014 (edited) Update: The proto board version has been made and is working. The final PCB layout will be in a separate thread documenting the process. Edited September 28, 2015 by ozfalcon Fixed Project Link Link to comment Share on other sites More sharing options...
ozfalcon Posted October 26, 2014 Author Share Posted October 26, 2014 (edited) Redundant Edited September 28, 2015 by ozfalcon Link to comment Share on other sites More sharing options...
Fire_Power Posted October 26, 2014 Share Posted October 26, 2014 Probably not what you want to hear but it looks an ideal application for an Arduino or PIC solution? Link to comment Share on other sites More sharing options...
ozfalcon Posted October 26, 2014 Author Share Posted October 26, 2014 Probably not what you want to hear but it looks an ideal application for an Arduino or PIC solution? I'm not sure i follow, This is controlled by a Mame PC with a Menu Frontend. [i'd better add that in somewhere!] Just prior to running the game, The wrapper script simply enables the coin device via LPT, Pacdrive or any other PC IO card. The PC already is doing the part of an Arduino or PIC microcontroller, Unless I'm missing something? Link to comment Share on other sites More sharing options...
andykmv Posted October 27, 2014 Share Posted October 27, 2014 since the 221 is not directly driving a load (ie using transistors to drive the loads) then consider using a 74HC221 - its a lower power CMOS part with a wider operating voltage range Link to comment Share on other sites More sharing options...
ozfalcon Posted September 6, 2015 Author Share Posted September 6, 2015 since the 221 is not directly driving a load (ie using transistors to drive the loads) then consider using a 74HC221 - its a lower power CMOS part with a wider operating voltage range I have decided to finally finish this circuit. As you suggested, I am now using the 74hc221. My circuit is working well but I'm not very experienced. Do you mind me asking a few basic CMOS related questions? The 74hc221 I am using seems to indicate output of 20mA max. With typical test/usage of upto 4mA (I only plan to use ~2mA). http://noel.feld.cvut.cz/hw/st/1924.pdf Does this sound correct or have I got it wrong? One last question I'm unclear about. From what I understand the 74hc series can drive LSTTL which would mean it sinks on low output. Is this correct? Link to comment Share on other sites More sharing options...
andykmv Posted September 7, 2015 Share Posted September 7, 2015 it sounds about right, although the 4ma if I read it correctly (a quick glance only) is for a possible fanout to upto 10 LSttl inputs for a typical 4.5v logic high. refer to the HCT_USER_GUIDE.pdf, Phillips, nov 25, 1997 - you should be able calculate the relevant figure using the details in that HCT family guide. the guide refers to source/sink - section 8 ? also, you may be able to save some mA by increasing the base transistors in the bcxxx transistors by moving upto 10k - depends how hard you are wanting to drive the transistors. Link to comment Share on other sites More sharing options...
ozfalcon Posted September 7, 2015 Author Share Posted September 7, 2015 (edited) it sounds about right, although the 4ma if I read it correctly (a quick glance only) is for a possible fanout to upto 10 LSttl inputs for a typical 4.5v logic high. refer to the HCT_USER_GUIDE.pdf, Phillips, nov 25, 1997 - you should be able calculate the relevant figure using the details in that HCT family guide. the guide refers to source/sink - section 8 ? also, you may be able to save some mA by increasing the base transistors in the bcxxx transistors by moving upto 10k - depends how hard you are wanting to drive the transistors. Section 8 of the HCT_USER_GUIDE.pdf should be helpful once I comprehend the relevant bits. I still don't quite understand the specs on fanout. ie. it's sink/source limits. Thanks for your help. Edited October 5, 2015 by ozfalcon Link to comment Share on other sites More sharing options...
andykmv Posted September 7, 2015 Share Posted September 7, 2015 where it talks about the results for different voltages, focus on the results for 4.5v (a nominal ttl high level) Link to comment Share on other sites More sharing options...
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