From 71ef715a88c69e3049831304cf35e5543e35d05e Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Sun, 27 Jan 2019 11:29:42 -0500 Subject: [PATCH] docs: Expand FAQ on why step_distance is used Signed-off-by: Kevin O'Connor --- docs/FAQ.md | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/docs/FAQ.md b/docs/FAQ.md index fb92b32f..83bc41a0 100644 --- a/docs/FAQ.md +++ b/docs/FAQ.md @@ -38,6 +38,14 @@ each motor driver pulse. It can also be calculated from the axis pitch, motor step angle, and driver microstepping. If unsure, do a web search for "calculate steps per mm" to find an online calculator. +Klipper uses step_distance instead of steps_per_mm in order to use +consistent units of measurement in the config file. (The config uses +millimeters for all distance measurements.) It is believed that +steps_per_mm originates from a micro-optimization on old 8-bit +micro-controllers (the desire to use a multiply instead of a divide in +some low-level code). Continuing to configure this one distance in +units of "inverse millimeters" is felt to be quirky and unnecessary. + ### Where's my serial port? The general way to find a USB serial port is to run `ls -l