Hi All,
Sorry about my english, I am braziliam, and my english not is good.
I am building a project, but i am not using microcontroler. I am using a 8255, one ADC0804 to convert A/D and 2 CD4066 to receive and send signals to Resistive Touch.
My problem is with send siginals ans read this signals. The logic os OK, but the voltage levels is floating or dont work.
I atached the image about my circuit (I do quickly because I am in my work).
How works (or at least how it should work, rssss). The 8255 send signals to select X or Y (sending +5v to X+ or Y+ and GND to X- or Y-). For this I am using a CD4066 to send this signals clear (I tried use transistor, but the voltage level of 8255, around 3v, was drinving every time the transistor). With CD4066 is WORK, the switch is "ON" or "OFF", this is work, but the exit voltage level when is "OFF" is floating:
Sample: When I select to read Y, switching "ON" and puting +5v in X+ and GND in X-, I switching "OFF" the Y+ and Y-, imagining that these 2 lines was in high impedance, but dont, this 2 lines, Y+ and Y- was around +1v and +2v respective. Is the same with another CD4066 to read the signals ans multiplex for the ADC0804 (wich have only one entrance to convert A/D).
Well, this is my problem. I have tried with 74LS125, same problem with high impendance, transistor, all time driving, I also tried one hammer and saw, but nothing, hehehehe...
Serious, any1 have any idea, or a circuito that work ?
PS: If any think wich I should work with microcontroler, and have circuit and programa for him, I apreciate. I'm not being lazy, but I tried to work with the ADC in 2 pics, 18F2550 and 16F628, and was the worst experience of my life, two weeks dumped's, nothing works.
Ty a lot,
Moacir Jr.
Sorry about my english, I am braziliam, and my english not is good.
I am building a project, but i am not using microcontroler. I am using a 8255, one ADC0804 to convert A/D and 2 CD4066 to receive and send signals to Resistive Touch.
My problem is with send siginals ans read this signals. The logic os OK, but the voltage levels is floating or dont work.
I atached the image about my circuit (I do quickly because I am in my work).
How works (or at least how it should work, rssss). The 8255 send signals to select X or Y (sending +5v to X+ or Y+ and GND to X- or Y-). For this I am using a CD4066 to send this signals clear (I tried use transistor, but the voltage level of 8255, around 3v, was drinving every time the transistor). With CD4066 is WORK, the switch is "ON" or "OFF", this is work, but the exit voltage level when is "OFF" is floating:
Sample: When I select to read Y, switching "ON" and puting +5v in X+ and GND in X-, I switching "OFF" the Y+ and Y-, imagining that these 2 lines was in high impedance, but dont, this 2 lines, Y+ and Y- was around +1v and +2v respective. Is the same with another CD4066 to read the signals ans multiplex for the ADC0804 (wich have only one entrance to convert A/D).
Well, this is my problem. I have tried with 74LS125, same problem with high impendance, transistor, all time driving, I also tried one hammer and saw, but nothing, hehehehe...
Serious, any1 have any idea, or a circuito that work ?
PS: If any think wich I should work with microcontroler, and have circuit and programa for him, I apreciate. I'm not being lazy, but I tried to work with the ADC in 2 pics, 18F2550 and 16F628, and was the worst experience of my life, two weeks dumped's, nothing works.
Ty a lot,
Moacir Jr.
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