Hardware Reference
In-Depth Information
Figure 9-7.
The MAX3232 circuit completed
The Power On
I hope you did the voltage test before this part. When you power on the Raspberry Pi, you won't see anything different
or new. After all, the Raspberry Pi can't talk to the MAX3232; it will only talk to the UART and that's always been there.
Now you're going to need a host PC with a serial port and some software to make use of the serial port.
I use a USB to RS-232 adapter with the Prolific PL2303 chip because it is well supported in Linux and does not
have any strange behavior. You don't need a null modem cable for the way I have wired the DB-9 shell. If you did want
to use a null modem cable, just swap pins 2 and 3 on the DB-9 shell. This would make it a little more like a normal
serial port but since I will only be using it for a console I don't mind.
You're also going to need some software to enable your client computer to communicate via the serial port. I like
to use Minicom; it's very handy and there is no need for an X-server when you need to configure a lot of serial devices.
However, there are many more applications that can talk to a serial port. First, install Minicom with this command:
# yum install minicom
Start Minicom with the
-s
flag to get you directly into the setup screen. In Figure
9-8
you can see the setup screen
for Minicom.
Figure 9-8.
The initial setup screen for Minicom
