View Full Version : SEROUT Wi-Fi mode

- 20th April 2017, 06:24
I am brand new to the Forum. Does anyone know if "SEROUT" wave is formatted to UART or RS232 format, I have been in contact with a Wi-Fi module chip manufacturer with a request of "Do I need to install a MAX232 chip to clean the wave from PicBasic function called "SEROUT", there answer was ""If the device connect to Wi-Fi module is RS232 interface then MAX232 chip is needed but not if UART".
The Wi-Fi module is 3v3.
Can anyone help with this question ?
Attached is the oscilloscope readings from inverted 9600 baud rate and true baud rate, judging by the High/Low voltage's it should have a MAX232 installed Does anyone agree with me?


- 20th April 2017, 06:32
If anyone needs the chip id's they are "PIC18F46K20" and the Wi-Fi is "USR-WiFi232 -D2"

- 20th April 2017, 10:57
You need to set your scope to DC coupling, not AC coupling.

According to the USR datasheet the serial connection is 3V3 uart levels. No MAX232 should be used.
You should run your pic at 3V3.

- 20th April 2017, 12:18
Thanks TumbleWeed,
The pic is running 3v3, my concern was that the generated signal from SEROUT was producing the signal in the images, but as you pointed out I set the sensor to DC from AC and the voltage measured 3v3(approx) so the generated neg-cycle was an error of the osciliscope.
ya only get what you pay for
So the answer is "SEROUT" produces TTL format

- 20th April 2017, 13:43
First, you need 3.3 V, so using MAX232 is a bad idea. MAX232 has 2 functions; invert the signal and boost the voltage. You do not want a bigger voltage! Run the PIC at 3.3V and you won't have to worry about level shifting.
If you need an inverted signal, you would simply use an inverter, or tell the PIC to send inverted. A quick check of the manual for PBP will tell you how to get SEROUT to produce TTL or inverted TTL.

- 21st April 2017, 02:28
Hi Charlie,
Yes the Wi-Fi module needs 3v3 TTL, the Max232 I was looking at was selectable 3v +/- to I think 8v +/- with a threshold voltage of 1v3 to 30v +/-.
The SEROUT function does produce a perfect square wave @ 3v3 and invertible but totally dependant on the pic used 3v3 verses 5v0 the same as the MAX232 does so that is good enough for me.
Thanking the forum for this info..