All Questions
14
questions
1
vote
0
answers
213
views
Custom ATMEGA2560 with RS-232 Communication Problem
I made a custom PCB using ATMEGA2560 with 2 MAX3223 RS-232 ICs (because they were available to me) but only one Tx channel is working on both ICs and I can't receive anything on any of them. I tried ...
- 11
-1
votes
1
answer
123
views
Why all the other ultrasonic sensors are getting triggered when only one so actually triggered?
I have an ultrasonic sensor, HC SR04, connected to the atmega 8 controller along with an LED for the indication purpose.
Let me discribe about my project with some anology.
Say I have 20 rooms( ...
0
votes
1
answer
1k
views
Atmega328p RS232 communication what's wrong?
I'm trying to connect Atmega328P to PC via RS232, the Microcontroller code is basically a : Serial.write("Greetings !"); inside the loop function.
I've tried the following circuit but it doesn't work ...
3
votes
1
answer
347
views
Capacitors for MAX232
I want to use this chip (ST3232CDR) as an RS232 transceiver. The problem is that I want to power the chip using 2 levels of voltage (3.3V and 5.0V) using a simple jumper, but in the datasheet (http://...
- 77
1
vote
1
answer
308
views
Questions about an atmega32 serial-bus to RS232 with converter and different logic levels
I have an atmega32 and a FUM DCF-U atomic clock (signal receiver and decoder) of HKW-elektronik. The µ-controller works with 5V and the module on 3.3V.
I have to build a converter, because the µ-...
- 145
1
vote
3
answers
11k
views
How to program an ATMega328 using a Serial Port without using programmers such as USBasp
I am currently learning electronics. I recently bought an ATMega328 and an USBasp programmer to begin my learning. But I couldn't use the USBasp to program my chip. So I researched on other ways to ...
1
vote
1
answer
647
views
No correct signal from ATMEGA162 UART
I got the following circuit:
simulate this circuit – Schematic created using CircuitLab
And this code to run it:
...
- 628
1
vote
2
answers
1k
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 ...
- 6,184
7
votes
2
answers
11k
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 ...
- 6,184
6
votes
4
answers
12k
views
Do I need MAX232 when using USB-to-Serial cable?
I am willing to build an AVR JTAG debugger (I grabbed from here: http://aquaticus.info/jtag) but the circuit uses COM port and it has MAX232 transceiver. My Laptop does not have COM port, so I need a ...
- 582
5
votes
3
answers
969
views
Square wave -5 to +5 volt at 500 Hz
I need to make a square wave -5 to +5 V at approx. 500 Hz - with small current. I have 0 (ground) and +5 V and a PWM (a Waspmote with a ATmega1281 microcontroller). I think it would be possible to ...
- 61
3
votes
1
answer
216
views
Microcontroller writes additional data on high-frequent writes
I'm using C-Control Pro 128 which contains a atmega processor. I've connected the rs232 interface with my PC and read the incoming data, having the following program executed on the controller:
...
- 175
6
votes
4
answers
5k
views
Do I have to use a MAX232 chip?
I am trying to interface my ATmega chips to the computer using a serial interface. I have read that this can be done directly by connecting the appropriate pin between the chips and the serial pin. ...
- 3,917
1
vote
2
answers
1k
views
Arduino + MAX232 + Pharos GPS360
I'm working on getting an ATMega168 to talk to my GPS that I ripped out of the casing from Microsoft Streets and Trips. I know it talks RS232 @ 5v (according to this post) and I just need to listen on ...
- 1,202