From 87564f145b1fa8892cc81f62e466bd73be465e87 Mon Sep 17 00:00:00 2001
From: Siddharth Purohit <siddharthbharatpurohit@gmail.com>
Date: Mon, 9 Nov 2020 13:41:20 +0530
Subject: [PATCH] AP_Periph: add docs for CAN SITL

---
 Tools/AP_Periph/README.md | 74 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/Tools/AP_Periph/README.md b/Tools/AP_Periph/README.md
index 9b79f103bb..86b7727215 100644
--- a/Tools/AP_Periph/README.md
+++ b/Tools/AP_Periph/README.md
@@ -95,6 +95,80 @@ parameter "FLASH_BOOTLOADER" to 1. After setting it to 1 the node will
 respond with a debug text message which can be seen in the UAVCAN GUI
 tool to show the result of the flash.
 
+# SITL Testing
+
+Currently GPS peripheral build is supported under linux environment,
+we simulate a UAVCAN GPS Peripheral on SocketCAN.
+
+Setup can be done as follows, this is on top of usual setup required 
+to build ardupilot:
+
+```
+sudo dpkg --add-architecture i386
+sudo apt-get update
+sudo apt-get install -y gcc-multilib g++-multilib
+sudo apt-get update
+sudo apt-get -y install can-utils iproute2 linux-modules-extra-$(uname -r)
+sudo modprobe vcan
+sudo ip link add dev vcan0 type vcan
+sudo ip link set up vcan0
+```
+Build Commands:
+```
+./waf configure --board sitl_periph_gps
+./waf AP_Periph
+```
+Autotest Command:
+```
+Tools/autotest/autotest.py -v Copter build.SITLPeriphGPS test.CAN
+```
+
+
+---
+**Note**
+
+To run valgrind on AP_Periph binary you might need to get 32 bit version of libc6-dbg which can be simply get using following command for Ubuntu machines: `sudo apt-get install libc6-dbg:i386`
+
+---
+
+
+https://github.com/linux-can/can-utils contains a nice set of utility to do CAN related testings on Linux system. I used Ubuntu for this development, for Ubuntu systems you can simply download this tool using `sudo apt-get install can-utils`
+
+Following are the common commands that can be used while testing or developing:
+* Create Virtual CAN Interface:
+```
+sudo modprobe vcan
+sudo ip link add dev vcan0 type vcan
+sudo ip link set up vcan0
+sudo ip link add dev vcan1 type vcan
+sudo ip link set up vcan1
+```
+* Route one CANSocket to another
+```
+sudo modprobe can-gw
+sudo cangw -A -s vcan0 -d vcan1 -e
+sudo cangw -A -s vcan1 -d vcan0 -e
+```
+* Delete routes
+```
+sudo cangw -D -s vcan0 -d vcan1 -e
+sudo cangw -D -s vcan1 -d vcan0 -e
+```
+* Route SLCAN to VCAN, this allows connecting CAN devices to SITL run via CAN Adapter like the one running in Ardupilot itself.
+```
+sudo modprobe slcan
+sudo modprobe can-gw
+sudo slcan_attach -f -s8 -o /dev/ttyACM0
+sudo slcand ttyACM0 slcan0
+sudo ifconfig slcan0 up
+sudo cangw -A -s vcan0 -d slcan0 -e
+sudo cangw -A -s slcan0 -d vcan0 -e
+```
+* Dump can messages:
+```
+sudo candump vcan0
+```
+
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