HellasTechn
- Apr 14, 2013
- 1,579
- Joined
- Apr 14, 2013
- Messages
- 1,579
No... i also had output scopings.Now I'm confused.
I thought all 4 images on #27 are measurements taken on the INPUT of the Max chip,aren't they?
No... i also had output scopings.Now I'm confused.
I thought all 4 images on #27 are measurements taken on the INPUT of the Max chip,aren't they?
I have one other question for you.
About a year ago i bought this USB 2.0 to TTL UART Serial Converter from e-bay.
http://www.ebay.com/itm/1pcs-6Pin-U...504639?hash=item33ae4b54ff:g:ViAAAOSwsB9WCNWw
Now how do i wire it up ?
PCB---- DB9
DTR to DRT
RXD to RXD
TXD to TXD
or do i need to connect for example RXD to TXD ?
Yes i want it to talk to PC serial port.If to DTE(like PC) connect crossed,and the DTR(of the adapter) to both DCD and DSR.
P.S.
I do not understand electrobrain's post ...
Probably because EB is unaware that you've shifted this thread from the MAX232 to a CP2102.I do not understand electrobrain's post ...
Try with some different R (for instance R=100Ω, R=1kΩ etc.)
Personally I love EB's Resistor fix for the MAX3232. It makes sense.
Both RXD and TXD give me +3.5 Volts. While i transmit data the TXD pin pulses to 0V which is normal.
Why the RXD line gives me +3.5 Volts ? also shouldn't the TXD line be +5 Volts when at idle state ?
Yes it does. Thank you for the circuit.USB/TLL(CP2102) module provides a +5V Vcc output.
I don't believe that Ivan has the stand alone chip. I think he said he purchased (Ebay) the complete USB/TTL converter. You'll have to search back through this thread to see where this thread switched tracks.Very important !!!
The CP2102 is not an rs232 compatible device,you have to add a rs-232 transceiver!!!
connecting it directly to a RS232 port will destroy the IC(in case the output of that port is larger than 5.5V,and smaller than -0.3v= which it will be!).
The device output of 3.5V at idle is fine since it is a CMOS device operated internally by a 3.3-3.45V voltage regulator.
I don't believe that Ivan has the stand alone chip. I think he said he purchased (Ebay) the complete USB/TTL converter. You'll have to search back through this thread to see where this thread switched tracks.
Chris
Oh,
He absolutely has the sand alone chip,that is what's on the module( #69).
It connects directly to USB and produces CMOS(TTL compatible) interface to the "rs-232 side".
From #73 you can confirm that the levels are 0-3.5v.
That isn't RS-232 compatible thus a rs-232 transceiver is absolutely needed !
I know i am mixing the posts right now but here is the question. According to your diagram Chris, the idle state of the rs232 is 15 volts (or could be up to 18 for hardware rs232 i think) while at the following link Christ clearly states that the idle state of a hardware rs232 is negative. look at his post #9Constantine, your concern over your logic being inverted is misplaced. A logic 1 on from the RS232 TX is Negative