Comments on: MAX232 Serial level converter

By: Manny

Manny — Thu, 27 Nov 2008 04:44:50 +0000

Can someone please e-mail me with a detailed pic of this all set up on a breadboardboard so I can replicate. I’ve been trying for months to get this to work off and on with no luck. I am Trying to debrick my router. I have a small white plastic breadboard. 1 DB9 and 6 1uf cylindrical caps and 6 .1uf ceramic caps but don’t have the 10uf cap but have a bunch of other sizes. Also have the max3232cpe can’t figure out how to work this. atesfaye@yahoo.com I thank you in advance!

By: L Bolton

L Bolton — Wed, 19 Nov 2008 01:49:03 +0000

I am about to build the circuit and note the .1 micofarad cap off pin 6 has the + to the ground line- is this correct?

By: mohsin

mohsin — Tue, 11 Nov 2008 19:55:49 +0000

hi,i m working with serial card but my card seems to give me dummy values.is there any thing wrong with my max232.i used 22mic f capacitor.also i want to know abt voltage value of capacitor.urgent.

By: heli

heli — Sat, 25 Oct 2008 15:57:57 +0000

plz any one tell me from where i can get the detail internal diagram of max232 ic….i also need to know what is the requirment of capacitor….

By: Noz

Noz — Sat, 25 Oct 2008 13:22:41 +0000

Reply to “Comment by 232:” Friday, July 18th 2008 at 3:07 am

how can I have the output of Tx to produce just 3.3V when it is at logic 1 ??
Is it the Vcc of the max232 just supply 3.3v??

_____________________________________________

You should really use something like a MX3232 IC based circuit.
This is available here (shamless plug):

http://www.tronisoft.com/4205.php

Hope it helps!

Noz,
Tronisoft
USB / RS232 / IO Modules

By: Trey Meyer

Trey Meyer — Mon, 01 Sep 2008 23:13:04 +0000

As a follow up to the above, I did hookup my scope in parallel and I am seeing a 7v swing from 0 (or +/- 7V) showing on the scope relative to gnd. This is with a purchased level converter from Solarbotics, Ltd.

By: Trey Meyer

Trey Meyer — Mon, 01 Sep 2008 22:35:24 +0000

Hello -

I left a message in Feb concerning ttl to rs232 conversion. You were generous with suggestions, but unfortunately the problem still exists. While I have worked around it for several months, I now need a hardware solution.

Here is the setup:
A microcontroller circuit needs to control a video switch via rs232. I cannot get the microcontroller to interface directly with the switch either with hand made level converters (using max232 or those I purchased premade).

I can, however, make it work if I interface the microcontroller to a PC com1, and then the PC com2 to the switch. A simple ‘copy com1 com2′ with timeout disabled (19200,8,n,1) allows the microcontroller to control the switch indirectly. There are only three wires used both from the controller to the PC and to the switch - tx,rx,gnd. There is no handshaking software or hardware enabled on any of the devices. The message I need to transmit is only a single character, and I only transmit from the controller to the switch (not bidirectionally).

I assume this must be to voltage levels required by the switch?

1) how can I measure the voltages present from max232? I have a scope, so can I just connect in parallel with TX and gnd and monitor the voltage levels?

2) Do you have a suggestion on another cct that will provide a greater voltage swing?

3) other?

Any help would be appreciated!
Trey

By: zed

zed — Wed, 13 Aug 2008 14:33:05 +0000

i only have 10uF capacitors available. Will it be OK to use 10uF capacitors for all the circuit or will it cause problems?

@232: i think you may have to use the 3232 chip which operates at LVTTL levels of 3.3v-5.0v. But if there is a way that anyone knows to get 3.3v from this max 232 chip I would like to know too!!!

By: 232

232 — Fri, 18 Jul 2008 03:07:28 +0000

how can I have the output of Tx to produce just 3.3V when it is at logic 1 ??

Is it the Vcc of the max232 just supply 3.3v??

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