From c2fec7be38bcf8fdfb1369f28006c77f7d509d82 Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Thu, 13 Aug 2015 01:55:27 +0300
Subject: [PATCH] STM32 driver: CAN timing docs

---
 libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp b/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
index ccd13ef802..f88600adc5 100644
--- a/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
+++ b/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
@@ -298,6 +298,12 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
 
     /*
      * Final validation
+     * Helpful Python:
+     * def sample_point_from_btr(x):
+     *     assert 0b0011110010000000111111000000000 & x == 0
+     *     ts2,ts1,brp = (BTR>>20)&7, (BTR>>16)&15, BTR&511
+     *     return (1+ts1+1)/(1+ts1+1+ts2+1)
+     *
      */
     if ((target_bitrate != (pclk / (prescaler * (1 + solution.bs1 + solution.bs2)))) || !solution.isValid())
     {