If Eric confirms the above, you will need three 74LS07 ICs.
Two for the counter output interface and one for the computer interface
Eric's reply indicates that you need non inverting buffers for the computer interface. So you need a total of three 74LS07 ICs, two for the counter interface and one for the computer i/f.0RESET0 said:Just for reference, I have taken a picture of the breadboard as it sits now.
It still has my old display. I moved some things around to get more room and it still works. right now only the ones digit is hooked up. I have hooked up each digit to it's respective decoder and they are all working correctly.
It looks like I will need to get another bread board to have room for the other three ICs that I need for the interfaces. If you make the multiplexer you will only need 7 resistors, so it may fit on the existing breadboard.
Alternatively, you could mount the displays and the 21 resistors on a piece of matrix board.
I will wait until Eric has reported in on the IC I need for the computer interface. I should have my new displays by then and have the circuit ready for the interface circuits.
Until next time...
Sean
P.S. I should have asked this before. Will I be able to run this circuit off of the same battery as the transmitter or should I plan on a separate power supply? You can use the same battery if you wish. But it would be more energy efficient if you used a 9 Volt battery for the ICs. If you use the 12 Volt battery, 7 Volts will be dropped across the Voltage Regulator and this wastes energy.
Whereas, if you use a 9 Volt battery, only 4 Volt is dropped across the regulator, hence almost 50% less energy is wasted.
0RESET0 said:Eric,
Am I missing something or did you not include a connection for a fire button?
I have connected all the pins on Len's circuit, there are still another 6 port pins available for 'other' functions, [ fire, etc]
Len,
I am having trouble getting my displays to work and I have not gotten the 74LS07s yet. I will try to get them next week.
Once I get the new ICs, I will be back to figure out this interface. I will try to make a complete schematic before I come back. Are there any easy to use programs out there that can do that kind of thing? Maybe even one that I could export and have a PCB made?
Are you using the multiplexing circuit or the non mux one?0RESET0 said:Eric,
Am I missing something or did you not include a connection for a fire button?
Pin 1 is the "fire button". A low on pin 1 turns Q1 on and thus turns the Tx on.
Len,
I am having trouble getting my displays to work and I have not gotten the 74LS07s yet. I will try to get them next week.
Once I get the new ICs, I will be back to figure out this interface. I will try to make a complete schematic before I come back. Are there any easy to use programs out there that can do that kind of thing? Maybe even one that I could export and have a PCB made?
Sean,0RESET0 said:I had a small epiphany last night while I was trying to sleep. The 8 bit counter that I bought is what they call tri-state. The encoder chip is also tri-state. Based on this, can I hook the counter to the encoder in a way that will net me all 6561 combinations?Does the tri-state on the counter mean that it has floating, Low and High as output states like the encoder has for the inputs? Yes & no, see below (I'm a poet and don't know it).
The encoder that we have been working with has the 12 pins that we were originally trying to connect to the 12 outputs from three BCD counters. These 12 pins are normally used as 8 pins for encoding and 4 pins for data. All twelve pins are tri-state. That gives me the 6561 combinations from the encoding and 81 more from the data pins. That gives me 531441 total combinations. I have not done the maths, but that sounds about right, ie. 12 ^ 3
Since I want my finished system to be expandable, I would like to use a tri-state counter to give me all the possible combinations. So, If the tri-state works as I have describes above, does anyone know a part number for an 12 bit up/down counter with tri-state outputs? Something similar to the 74F579 that I have but not as fast.
Sean,0RESET0 said:Alright, it has been a while but I am back to get this finished. I have the counter circuit complete and working minus the interface circuit. I have been reviewing everything and I think I have found something that Isn't going to work. The Interface circuit is taking the output from the counters. These counters have a BCD output. I need a true binary input for encoder, otherwise I will lose several combinations and my switching won't work the same on the Rx decoder. For instance. 12 from the counters would be 0001 0010 while 12 for the Rx is 1100. THe only way I see out of this is my original plan to have two counters with the same inputs so that I know that they count at the same time. So, I will still be using the interface circuit but the buffers will have to connect to the outputs of two 4 bit binary counters.
Len, Eric, Will it still work that same way?
Thanks
Sean
ljcox said:Sean,
You're misunderstanding the Tri State.
You're assuming that any output can be L, H or TS. Not true. When the outputs are set in TS, all outputs are in TS.
TS is used for "bus" connections. For example, several RAM memory chips could be connected to the same data bus. All are normally in TS, but when the CPU wants to address a particular chip, it disables the TS of that chip only so its outputs are connected to the bus so that data can be transferred to the CPU from that chip. I suggest you do an internet search for TS.
Yes, this would be the best option.0RESET0 said:Len,
is there something like a display driver that can take the binary out and run a 7-segment? I have three BCD to 7-seg now, is there a binary to 7-seg?
This would allow me to run only one counter and still have the decimal display to know what channel I am on.
If this is not an option, could you explain the BCD to binary conversion? Will it work the same as what I mentioned above except it would be a BCD counter and have the output going to the driver and the converter?
Thanks
Sean
This is a good site for general info.0RESET0 said:I found this site,
https://www.asic-world.com/digital/gates5.html
At teh bottom of the page, he explains TS. Is this correct? yes Right now I don't understand most of it. All I see is H, L and floating. Just like we have on my encoder chip.
Are you saying that TS outputs and TS inputs are not the same? Yes & no
Thanks
Sean,0RESET0 said:OK,
I have gone over some things and I have a question. On a normal counter like the ones I am using, The active output state is high correct? Yes but a counter with AL outputs would be unusual. What is the state of the outputs when they are not active? The attachment may help you.
I thought I read in here that they are floating. No If both of these assumptions are true the would not the same be true for a counter that has active outputs low? If all of these assumptions are true then would a counter chip with the capability of high or low outputs have three possible states, High, Low and Floating? No
Am I totally wrong on this or what? I think I may have confused the issue when I mentioned tri-state. As I see it, a tri-state has a different three states, High, Low and high impedance Yes with the high impedance being applied to all output pins when it is active. This is ambiguous. The Hi Z state is applied when the outputs are disabled. Tri State is used for bus connections, as I explained previously. It does not help you with your situation.
Are these definitions correct? -
Floating - having neither a high or low state but a voltage that falls below the high threshold and above the low threshold. Floating means open. You're right in the case of the PT2262 IC. when open, the voltage is between the upper & lower thresholds. The internal logic determines whether the input is F, H or L, ie. if the input voltage is > the upper threshold, then it is seen as a H, If it is < the lower threshold it is a L. If the input is open (or the voltage is between the upper and lower thresholds) it is F.
High impedance - not connected, the same as physically disconnecting. This is essentially correct. The internal circuitry is disconnected from the output pin. So the output pin would appear to be open if you measured it.
Sean
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