RS-232 is the electrical standard used on most serial ports.

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25 views

MAX3232 overheating/burnt after connecting to PC

Okay hi. I've got a MAX3232 Serial-to-TTL RS232 board which I am currently using in factory assembly lines. I don't have its picture, but here's a similar product: sample This is the circuit I've ...
5
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5answers
2k views

Why are there so many resistors in a typical schematic?

I know that some resistors cause pull-up or pull-down or work as a voltage divider and/or current divider. But sometimes I cannot understand their function in some simple circuits: Take this motor ...
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2answers
56 views

Simple FPGA serial communication not working

FPGA board (manual) USB-to-RS232 cable (controller) synthesis reports I created a simple schematic which shorts the TXD and RXD pins according to the manual. However, when I use RealTerm to send ...
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0answers
48 views

Send AT commands to UART device, what am I missing?

It all started with me wanting to change the pairing code of a bluetooth device, and now I'm knee-deep in electronics... I have a miniELM327 bluetooth interface with PIN "1234" , I want to change it. ...
3
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0answers
63 views

For which type of serial communication is Arduino Severino designed? [migrated]

Arduino has become quite costly where I come from (2/3 of the price of Raspberry PI) so I have created an Arduino Severino clone. I had used the device with the RS-232 Usb-Serial converter. But after ...
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2answers
341 views

Can I split one RS232 output signal into two signals? [duplicate]

I have one controller which processes data from a weigh scale. With it I can capture data using hyper terminal on a PC (RS232 communication - standard DB9 connector). Now I want to analyze it on ...
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2answers
39 views

MCU cannot communicate with Bluegiga WT12 module

I have the evaluation kit EK-WT12 for Bluegiga WT12 module being controlled by a TI Launchpad. I have used the evaluation kit to communicate to a computer with SPP profile and I have sent and received ...
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0answers
44 views

USB CDC RS-232 interface to Bluetooth or WiFi

I have a device that communicates with a computer via an USB CDC RS-232 interface. The thing is that I want to build an interface (on top of that USB interface) that enables the device to ...
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3answers
186 views

Can you safely “short circuit” 2 signals when they compete for the same pin to avoid having to use a multiplexer?

I'm developing for a very limited, 8 pin LPC810 microcontroller and have to connect multiple signals on a single pin. Obviously, if there's only 1 output signal on a bus, that should be OK, but what ...
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0answers
78 views

UART RS232 Converter via MAX232 malfunctioning?

I am a newbie, trying to test Launchpad Tiva's UART channels. I have set up the circuit in order to connect my Launchpad's UART to RS232 port of my PC. However I have the following problems, which I ...
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1answer
67 views

USB to Serial cable and VCC current output [closed]

I have question about generic USB TTL Serial cables, FTDI FT232R-based. The cables differ in voltage, 5V, 3.3V and output current. USB TTL Serial Cables I need a cable for a USB to serial ...
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2answers
48 views

FPGA able to send data, but unable to receive data. (UART - RS232)

I have a DE0-nano FPGA board and I am trying to establish a serial connection with my PC. I am using the RS232 implementation from here: http://www.fpga4fun.com/SerialInterface.html I have tested ...
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2answers
67 views

Serial comms over 3m cable, shared with USB

I am designing a system that needs to do serial comms over a standard USB cable, as well as normal USB (but not at the same time). In other words, when plugged in to a PC it will appear as a USB ...
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1answer
79 views

Connecting to pins on USB to Serial module (contains FT232RL chip)

I have this module: My question pertains specifically to the RX and TX pins shown (sorry for having it upside down, only way I could make it look clear.) I don't understand why there are 4 pins, ...
17
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3answers
2k views

Difference between UART and RS232?

Most of the time RS232 and UART come together in serial communication theories. Are they both the same? From my readings I concluded UART is a hardware form of RS232 protocol. Am I correct?
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2answers
175 views

Connect DHT22 to serial connection

I'm trying to find a way to connect a temperature and humidity sensor DHT22 to an XBee's RX/TX pins without an additional microcontroller(Arduino or anything that needs software) or reprogramming the ...
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2answers
72 views

How can I know whether a random “known not TTL” RS232 device will work with any old random USB-RS232 converter?

I've been hunting around for RS232 converters for a little while now, trying to get my head around the way RS232 works (or at least how it's supposed to), and the way RS232-USB converters (more ...
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1answer
182 views

How do the TX/RX/CTS/RTS/DSR/DTR/DCD/RI/GND signal monitor LEDs on these odd FTDI-based USB-RS232 converters work?

While searching for a "decent" USB-RS232 converter, I turned up the following two fascinating creations which have status LEDs for all the signal lines: This concept really appeals to me from a ...
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2answers
68 views

Do you really need all of the sigals for a general RS-232 port?

I know that having TX, RX, GND, RTS, CTS are good. What about all of the others? Do devices these days even make use of the other pins (DSR, RI, DCD, DTR)? Is it safe to generally leave out these ...
2
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0answers
87 views

pic24fj128ga310 uart not working in application, but works with PuTTY

I'm trying to connect a PIC24FJ128GA310 mounted on an Explorer 16 board with an embedded wireless module. I have been able to set up both to communicate perfectly well with PuTTY (an equivalent to ...
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2answers
175 views

Speed problems in homemade RS232-to-TTL converter board

I'm still trying to debug this RS232-to-TTL converter board that I've made, shown below. Now I think I've narrowed down the problem to speed: it works fine at 57,600 baud; but it inserts some ...
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1answer
81 views

Is it possible to use the RTS pin as DTR?

I'm deveoloping a project with a raspberry Pi that involves serial communication. In order to properly handle voltage levels, I used a max3232 converter between the raspberry and the external device ...
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2answers
505 views

Problems with homemade RS232-to-TTL converter board based on TI's MAX232

I've designed an RS232-to-TTL converter board based on TI's MAX232 IC that I plan to use to program a few custom Arduino boards that I have. However, I'm having trouble with the board and I'm hoping ...
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0answers
55 views

Why can't I use my AVR programmer with serial functions?

I recently created a project in which I made my own AVR test bed based on the Arduino Uno. I used the ATmega 328P and I have set up all the fuses for the external clock and the Arduino IDE to ...
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2answers
138 views

3.7v > 3.3v voltage stepdown with logic-driven on/off control [paused]

(PAUSED): This topic is currently on hold as I source necessary hardware. I need to connect a Wi-Fi/RS232 module to a low-powered monitoring device, and for maximum portability, I'd like to power the ...
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1answer
131 views

Voltage level too low for MAX232

I'm trying to connect TI's MAX232 to my Arduino so that I can communicate with my PC. I have connected it exactly as the picture shows: Tx/Rx are not connected because I just wanted to see if I can ...
3
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3answers
364 views

Can I screw up my board by guessing which RS232 pins are which?

I have a Raspberry Pi that I want to hook up to a serial (RS232) cable. I've found and read some information about this, so I know what pins on my RPi are Rx/Tx/3.3V/Gnd... Now the cable I'm hooking ...
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1answer
100 views

Connecting 4 devices on RS232

I have two PCs (very old, without usb but rs232 port) that talks via RS232. They send to each other very small bit of info ( one character every 10sec). Now I need to connect additionally two sensors ...
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0answers
90 views

RS232 Grounding question

I want to connect 2 devices together using RS232. I initially thought both devices used the power ground as the reference signal for their RS232 (they're powered by the same PSU) so I designed my ...
2
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3answers
190 views

When do we use all pins in RS-232 cable?

I think the minimum for simplex communication are TX so we can transmit and the power supply pins +Vcc and GND. That is all we need. When do we need to use all 9 pins of RS-232? I think that the ...
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2answers
282 views

How would I make an Arduino Due recieve RS-232/422 signals?

Background on this question is here: Oops, I accidentally need to build an embedded system. What would that look like? I'm looking at purchasing an Arduino Due to take in 3 (well, ultimately 5, but ...
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3answers
438 views

What can I do to decrease the latency from these serial ports which are attached to a PC via a Serial to USB adapter?

I think I have accidentally discovered a need in my life for embedded systems. Which is great! And kind of scary. And I need help. Background: I got hired to build a GUI application which takes scans ...
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0answers
107 views

FT2232H as USB to MCU UART configuration using D2XX

I'm having trouble using the FT2232H as a USB to MCU UART bridge. I was able to open the device using and set the baud rate using D2XX commands. However, I cant see any UART output in my logic ...
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2answers
250 views

Connect Arduino to RS232

I have a device that is powered by the Arduino (+5V). The device (a VC0706 Powered camera), incomporates a MAX3232 to convert to RS-232. Unfortunatly, I don't have the tools or dexterity to remove ...
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1answer
121 views

Honeywell Dead Reckoning Module GPS Problems

This was previously posted in the Stack Exchange forum and I was referred here. I'm currently trying to connect a Honeywell DRM4000L to a GPS module. The DRM is a dead-reckoning device which takes a ...
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2answers
150 views

Getting started with an LPC1313 Microcontroller [closed]

I recently purchased this microcontroller along with an FTDI TTL-232R-3V3 cable. I want to program a blinking lights hello world application onto the microcontroller. I was told that I might be able ...
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2answers
175 views

Is “RS-232 Cable” a valid term?

As "RS-232" is a Protocol/Standard, "DB-9" is a type of Connector, Is RS-232 Cable a valid term? Or is there any proper name for that? "Serial Cable" maybe!
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4answers
106 views

How is it that this transistor drives the line such that we get a RESET event?

I am a bit confused on how this schematic works. It looks as if when we do not have any data coming in (i.e. 0V constant) from pin 3 on the DB-9 then the transistor will be off and the RESET will be ...
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2answers
290 views

Holding register in microcontroller for Modbus RTU

I'm very noob in microcntroller modbus. I want to do Modbus RTU slave device using RS232. I read modbus documentation from modbus.org site. But still I'm not clear about few things. How to define the ...
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3answers
674 views

RxD TxD equivalent pins in USB

I want to build a USB Programmer currently for AT89C51. I am stuck on how to make it communicate with PC. In RS232, the RxD TxD pins are straight forward, we just need to use Logic Level Converter to ...
2
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3answers
85 views

How to write to block memory?

I need to write 16x16 bit data to block memory. I am using RS232 to send data. To get 16 bit data, I send 2x8bit. Now, how can I write my data to the memory? I have a write signal and 16 bit input ...
0
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0answers
208 views

Can I get by with Max232 clone programming Arduino Mini Pro?

Do I need USB->RS232 converter (FTDI or the likes) to program Arduino Mini Pro with a PC, or can I use just a RS232C->RS232 converter (MAX232 clones)? I happen to have the latter, but would need to ...
0
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1answer
107 views

Looking for a serial 9800 baud device that can input a string and output a modified string

I'm looking for a simple programmable device that has RS232 inputs and outputs that can take a string of ten numbers and output a modified string over 9800 9600 baud, 8 bits, 1 stop bit, parity: ...
0
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1answer
141 views

RS232 and realterm communication problem

I am not seeing anything on a port in realterm though it is properly sending the data through the port. Anyone run into a similar situation? What am I doing wrong? I am using a C8051F120 developers ...
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1answer
155 views

Serial Port Terminal transmitting at 300 baudrate

I have been using Hercules SerialPort Terminal for a while now and its pretty cool. But now, I need to send data's at 300Baud, but Hercules stops at 9600baud. I find TeraTerm which looks okay as ...
3
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7answers
406 views

Best PC interface for simple custom hardware

What interface of your PC do you use in order to connect to simple custom hardware? The most commonly used interface was RS232 some while ago and today is probably USB, but wouldn't it be simpler for ...
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1answer
114 views

Easiest way to detect a button push

I have a button that when push turns on a little light (light blinks; like a counter) - is there an easy way to hijack this signal so that my windows box can also detect if the button is pushed? I ...
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4answers
625 views

USB to Serial Converter using the CDC/ACM specification

I try to use a Usb to Serial converter in a windows store application. As the windows store application does not Support SerialPorts i need to find a USB/Serial Converter that supports CDC/ACM. Here ...
0
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1answer
218 views

RS232 and RS422 (Isolated and ESD Protected)

I want my RS232 and RS422 to be galvanically isolated and ESD protected. I have two options to implement this requirement. Option 1: MCU-->OPTO-->DRIVER-->ESD PROTECTION Use MAX3232 for RS232 ...
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0answers
80 views

TI MAX3237 TTL / RS232 transciever, transmission not working

I've got a TI MAX3237 5 TX / 3 RX transceiver (TI datasheet, Maxim datasheet) set up as follows: The supply is 3V3 from a BeagleBone Black, measured at 3.35v. The CMOS level inputs and outputs ...