2.12.2 Configuring PPP Connection over UART4

Here is an instruction on how to configure PPP connection over UART4 on a TI AM3359 ICEv2 (TMDSICE3359) board.

By default, the pppd service is running on the UART4 port ready for connection via null-modem cable with PC. UART4 signals are routed to J3 connector (Host Expansion Connector 2) of ICEv2 board. To connect the null-modem cable you need to use the following pins of the J3 connector:

Signal

Host Expansion Connector 2 (J3)

GND

Pin 2

RX

Pin 7

TX

Pin 8

To establish a connection on the PC side you need to run the pppd service with the following command:

# pppd nodetach local lock noauth nocrtscts passive <IP-1>:<IP-2> <serial-device> <baudrate> &

Where:

<IP-1>

IP address of host PC (e.g. 172.16.0.100) for PPP connection;

<IP-2>

IP address of the ICEv2 board (e.g. 172.16.0.1) for PPP connection;

<serial-device>

Serial device name (e.g. /dev/ttyS1);

<baudrate>

Serial port baud rate (115200 by default). If you need to change the baud rate, you should also do it on the AM3359 ICEv2 board in the configuration file /etc/config/network` (section config interface 'uart4', option pppd_options) and execute command

[root@tanowrt ~]# ubus call network reload

2.12.2.1 Example

For example, if host PC has a serial device named /dev/ttyS1, the IP addresses of the PPP connection should be assigned to 172.16.0.100 (host PC) and 172.16.0.1 (ICEv2 board), then pppd should be started with the following command:

# pppd nodetach local lock noauth nocrtscts passive 172.16.0.100:172.16.0.1 /dev/ttyS1 115200 &

After executing this command on host PC you should see the ppp0 interface with the assigned IP address 172.16.0.100:

# ifconfig ppp0
ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOART,MULTICAST>  mtu 1500
          inet addr:172.16.0.100  netmask 255.255.255.255  destination 172.16.0.1
          ppp  txqueuelen 3  (Point-to-Point Protocol)
          RX packets 14  bytes 293 (293.0 B)
          RX errors 0  dropped 0  overruns 0  frame 0
          TX packets 11  bytes 119 (119.0 B)
          TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Now you can access AM3359 ICEv2 board from host PC using IP address 172.16.0.1. For example, you can test it with the ping command:

# ping 172.16.0.1
PING 172.16.0.1 (172.16.0.1): 56 data bytes
64 bytes from 172.16.0.1: seq=0 ttl=64 time=21.212 ms
64 bytes from 172.16.0.1: seq=1 ttl=64 time=22.162 ms
64 bytes from 172.16.0.1: seq=2 ttl=64 time=22.233 ms
64 bytes from 172.16.0.1: seq=3 ttl=64 time=22.186 ms
64 bytes from 172.16.0.1: seq=4 ttl=64 time=20.161 ms
^C
--- 172.16.0.1 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 20.161/21.590/22.233 ms