Data Transmission Stop from Raspberry Pi

1
votes

I am trying to establish a communication b/w raspberrypi(Raspbian) and PC(Microsoft XP) through GPIO PINS 14(Tx) and 15(Rx) for sending/receiving data... , RS-232 level converter is using for connection of GPIO to PC serial COM port and Voltage conversion from 3.3V to 12V... I install minicom (Echo ON) at raspberry side and install Teraterm(ECHO OFF) at PC side.

Whatever I typed on minicom, it successfully appear on Minicom and Teraterm but when I tried same thing on Teraterm, it only appears on Teraterm not on minicom and also blocked by minicom (/dev/ttyAMA0). After that I am not able to send data from minicom to Teraterm.

But I just check one thing more and very surprise that, when shorting GPIO PIN 14& 15 together and starting typing on minicom... it just show me one character and stop after that...

Again I repeat whole process by closing/opening minicom, again it just show character and then stop.

Can you plz guide me why it happening and how do I resolve it?

1
raspberry-piwindows-xpraspbiangpioserial-communication

1 Answers

1
votes

I just read from this link that someone was also facing your kind of problem but not exactly what you are facing.

It is happened because Kernel takeover the control on console so It is good and very important to disconnect the connect of console and kernal from the startup.

Now you can follow these step, I am sure you will get rid from this trouble...

Start editing this file by this command

sudo vi /boot/cmdline.txt

Originally it contained:

dwc_otg.lpm_enable=0 rpitestmode=1 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait

deleted the two parameters involving the serial port (ttyAMA0) to get the following:

dwc_otg.lpm_enable=0 rpitestmode=1 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait

rebooted (sudo reboot) to confirm that kernel output was no longer going to the serial port. But the serial console was still available. So edited /etc/inittab:

sudo vi /etc/inittab

commented out the following line:

2:23:respawn:/sbin/getty -L ttyAMA0 9600 vt100

Finally, rebooted again and confirmed that nothing was touching the serial port anymore. Then, to test it out installed minicom on the Raspberry Pi:

sudo apt-get install minicom

And ran it:

minicom -b 9600 -o -D /dev/ttyAMA0

After, it is able to send data in both directions!