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source/_posts/2019-08-11-arduino-boot-loader-on-cheap-chinese-bluepill-clone.markdown

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+---
+layout: post
+title: "Arduino boot loader on cheap Chinese BluePill clone"
+date: 2019-08-11 16:59:46 +0200
+comments: true
+categories: 
+---
+
+Boot modes: flash/ROM (system memory)/RAM
+Bootloader or not/purpose/various programming methods
+  * UART
+  * ST-LINK
+  * DFU
+Arduino boot loader: dual device issue (serial ACM vs DFU)
+  * reset -> loader (3s) -> user app
+  * when ACM app detects DTR toggle, reset USB bus (or reset MCU???)
+    and switch back to DFU loader
+  * rogerclarke
+  * support recently integrated in official STM32duino
+Bare boot loader: DFU only, by default one shot at reset, no support
+for switching back through DTR (no ACM!)
+Requires a sketch which implements the ACM dev (SerialUSB)
+For some reason the distributed combined loader+sketch does not
+work.
+Perpetual loader mode (stay in DFU)
+Once first sketch is programmed, it contains ACM support for
+loading the next one... *If* the correct programming mode is
+selected while building the sketch!
+
+Alternative: HID bootloader (not thoroughly investigated)
+
+Reliability issue (host sometimes unable to open ACM)
+
+ST-LINK is superior (no 3s delay at boot time, reliable programming)

source/_posts/2019-12-24-poor-mans-cnc-plotter.markdown

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+---
+layout: post
+title: "Poor man's CNC plotter"
+date: 2019-12-24 15:36:20 +0100
+comments: true
+categories: 
+---
+
+Initial GRBL settings:
+
+````
+$0 = 10    (Step pulse time, microseconds)
+$1 = 25    (Step idle delay, milliseconds)
+$2 = 0    (Step pulse invert, mask)
+$3 = 0    (Step direction invert, mask)
+$4 = 0    (Invert step enable pin, boolean)
+$5 = 0    (Invert limit pins, boolean)
+$6 = 0    (Invert probe pin, boolean)
+$10 = 1    (Status report options, mask)
+$11 = 0.010    (Junction deviation, millimeters)
+$12 = 0.002    (Arc tolerance, millimeters)
+$13 = 0    (Report in inches, boolean)
+$20 = 0    (Soft limits enable, boolean)
+$21 = 0    (Hard limits enable, boolean)
+$22 = 0    (Homing cycle enable, boolean)
+$23 = 0    (Homing direction invert, mask)
+$24 = 25.000    (Homing locate feed rate, mm/min)
+$25 = 500.000    (Homing search seek rate, mm/min)
+$26 = 250    (Homing switch debounce delay, milliseconds)
+$27 = 1.000    (Homing switch pull-off distance, millimeters)
+$30 = 255    (Maximum spindle speed, RPM)
+$31 = 1    (Minimum spindle speed, RPM)
+$32 = 0    (Laser-mode enable, boolean)
+$100 = 6.700    (X-axis travel resolution, step/mm)
+$101 = 8.000    (Y-axis travel resolution, step/mm)
+$102 = 250.000    (Z-axis travel resolution, step/mm)
+$110 = 4000.000    (X-axis maximum rate, mm/min)
+$111 = 4000.000    (Y-axis maximum rate, mm/min)
+$112 = 500.000    (Z-axis maximum rate, mm/min)
+$120 = 500.000    (X-axis acceleration, mm/sec^2)
+$121 = 500.000    (Y-axis acceleration, mm/sec^2)
+$122 = 10.000    (Z-axis acceleration, mm/sec^2)
+$130 = 40.000    (X-axis maximum travel, millimeters)
+$131 = 30.000    (Y-axis maximum travel, millimeters)
+$132 = 200.000    (Z-axis maximum travel, millimeters)
+````
+
+Switch to 16x micro-stepping:
+````
+>>> $100=107.2
+ok
+>>> $101=128
+ok
+````

source/_posts/2023-05-06-color-emoji-terminal.markdown

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+---
+layout: post
+title: "Color emoji in mate-terminal on Debian"
+date: 2023-05-06 00:58:00 +0100
+comments: true
+categories: 
+---
+
+Easy peasy: `apt install apt install fonts-noto-color-emoji`