I have two transmitters, 1st is Device 1 and 2nd is Microcontroller.Hi,
One transmitter, multiple receivers is no problem.
Klaus
I have two transmitters, 1st is Device 1 and 2nd is Microcontroller.
I see only one Tx in this question.Can I just connect Tx of device1 and microconroller with Rx of Device 2 with out using Diode and pull down resistors?
No no. My bad, may be I mistakenly type it. actual scenario have two transmitter and I asked if i don't use diode then what will happen or can I not use diodeHi,
In post#6 you asked this.
I see only one Tx in this question.
Klaus
Do you know where to put a pull-down resistor and of what value? kindly guide me, is it before diode or after diode? and is the direction of diode will be reverse?I think he does not understand what is a basis of electronics, no matter
Dear FvMI believe the question was already answered.
regarding your question why RS232 at all this is because other two devices (Device1 and Device2) are of other company and they are using RS232 Signaling. So at microcontroller side I have to use RS232 signaling as well.Hi,
I have to admit that my post#3 wast partly wrong.
If you really use RS232, then idle HIGH means low voltage.
Thus the diode orientation of post#1 is correct. Anode to RS232 transmitter. You need a resistor to -Vs.
*****
Now the qestion: why RS232 at all?
What baud rate, what wire length, what cable type?
Klaus
For the collision,Signal-level-wise, post #14 scheme works correctly. But it doesn't solve the problem of possible signal collisions if both transmitters are sending simultaneously. In contrast to a multi-drop RS-485 network, the transmitters have no means to detect collisions directly.
Signal-level-wise, post #14 scheme works correctly
Dear KlausSTHi,
Correct me if I'm wrong:
UART is idle HIGH, TTL level HIGH, RS232 voltage negative.
So in idle state
* upper RS232 driver drives negative through diode (sadly the schematic misses designators for clear communication)
* upper resistor pulls negative
* lower RS232 driver drives negative through diode
* lower resistor pulls negative
I see no possibility for the drivers to pull positive, and the resistors don't anyways.
So how can the receiver see positive voltage = logically LOW?
Still to consider: (besides the bus collission problem)
What happens to the signal levels if one driver is not powered up?
Also how does the unpowered driver react in this case?
Klaus
--- Updated ---
Added...
Post#18: I can't see how the microcontroller can detect that device 1 is sending.
There is no connection from device1_Tx to microcontroller_Rx. (Referring to schematic of post#1)
Microcontroler Rx just sees device2_Tx .... but this does not solve the collission problem .... unless there is a specified time scheme.
Klaus
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?