I recently started playing to Raspberry Pi. Along with other questions I wanted to try talking to RPi via a serial cable. The says that at reset only pins GPIO 14 & 15 (TxD, RxD) are assigned to the alternate function UART. So, it should work out of the box. I decided to buy.
Download MochaSoft software for Mac OS X The products tn5250 and tn3270 can be tested before you actually buy them. The trial is valid for 30 days. The products are fully functional. When you order, we will send a software license code, which will remove the 30 days limit.
It was available on eBay as. This cable provides 3.3V output levels which are strongly recommended for RPi (not 5V), and its 3 wires with female plugs can be directly connected to the RPi GPIO P1 header. Unfortunately, at a time of this writing, there were no drivers for Mac OSX available on the, and OSX Lion (10.7.4) didn’t recognize this device. It was an unpleasant surprise because before I saw that Lion perfectly recognized other USB-RS232 hardware based on different chipsets (Microchip, for example). I checked the Product ID and Manufacturer on the Olimex cable. When the cable is connected, click on “About This Mac More Info System Report USB”. Googling for a Prolific driver for Mac brought me to a great blog post, called “”.
Following the instructions I installed the driver and connected to Raspberry Pi. In short I did the following: cd /tmp wget tar xvzf cd osx-pl2303.kext sudo cp -R osx-pl2303.kext /System/Library/Extensions/ cd /System/Library/Extensions chmod -R 755 osx-pl2303.kext chown -R root:wheel osx-pl2303.kext cd /System/Library/Extensions kextload./osx-pl2303.kext kextcache -system-cache Note: Just in case, I made a copy of the “” file.
You can make sure that everything is installed correctly by: kextstat -b nl.bjaelectronics.driver.PL2303 It should print the following: Index Refs Address Size Wired Name (Version) 74 0 0xffffff7f808ee000 0xb000 0xb000 nl.bjaelectronics.driver.PL2303 (1.0.0d1) Note: If you need to unload the driver for some reason, you check that the driver is loaded (by kextstat command above), and then: sudo kextunload /System/Library/Extensions/osx-pl2303.kext When the driver is installed, reconnect the cable to USB. There should be two device drivers created /dev/cu.PL236 and /dev/tty.PL236.
You can check it by: ls /dev/.PL. It should print: /dev/cu.PL236 /dev/tty.PL236 Now let’s connect the cable to the RPi header P1. It’s better to disconnect it from USB temporarily.
The pinout of the cable is the following: Wire Desc Rip GPIO Blue GND 0v Green Rx 14/TxD Red Tx 15/RxD An example of the connection: When all three wires are attached, you can connect the cable back to USB. Now any terminal emulator software can talk to RPi via the /dev/cu.PL236 device. I used Minicom: minicom -D /dev/cu.PL236 -b 115200 It should print something like this: Welcome to minicom 2.6.1 OPTIONS: Compiled on May 10 2012, 07:16:49. Port /dev/cu.PL236 Press Meta-Z for help on special keys Debian GNU/Linux 6.0 raspberrypi ttyAMA0 raspberrypi login: Finally, you may want to re-direct the RPi console from HDMI to the serial port (ttyAMA0). In this case RPi will be printing boot messages to the serial console instead of the monitor. You need to login to your RPi (via SSH, telnet or just established serial connection) and execute the following: sudo mount /dev/mmcblk0p1 /mnt This will mount your boot partition to /mnt. Now you need to edit the kernel commund line: sudo vi /mnt/cmdline.txt In cmdline.txt make sure that console=ttyAMA0,115200 and kgdboc=ttyAMA0,115200, and there is no another console= assignment, for example to tty0.
After you save the changes and reboot RPi, you may see RPi boot messages in the terminal emulator connected to /dev/cu.PL236.