From eb1c72b72bc663239ae229eae8c5c05ca4846a1d Mon Sep 17 00:00:00 2001
From: Selene ToyKeeper
Date: Thu, 1 Apr 2021 23:16:58 -0600
Subject: added attiny1616 flashing instructions, and made flash-tiny1616.sh
 configurable via environment variables

---
 README                | 35 +++++++++++++++++++++++++++++++++--
 bin/flash-tiny1616.sh | 13 ++++++++++++-
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/README b/README
index 324e489..816475b 100644
--- a/README
+++ b/README
@@ -131,10 +131,41 @@ working.
 
   - Set ATTINY_DFP=/path/to/where/you/unzipped/the/pack
     (either in your shell, or in this repo's bin/build.sh script)
- 
+
+    export ATTINY_DFP=$HOME/src/torches/atmel/attiny-dfp
+
   - Make sure you're using gcc-avr 1:5.4.0+Atmel3.6.2 or newer.
     3.6.1 will not work.  It gives errors like:
     /usr/lib/gcc/avr/5.4.0/../../../avr/bin/ld: address 0x80381e of anduril.elf section `.data' is not within region `data'
     This requires debian/bullseye or newer; buster has 3.6.1.
- 
+
 This should at least allow the code to compile.
+
+Some extra steps are also needed to make flashing (avrdude) work:
+
+  - Get an AVR jtag2 device.
+    The one I'm using is: "HWAYEH AVR JTAG ICE Version 2.0"
+    Connect the cables:
+      - GND   = -
+      - Vtref = +
+      - nSRST = R (reset/UPDI)
+
+  - Flash the jtag2 device with the relevant firmware:
+    https://github.com/ElTangas/jtag2updi/tree/master/tools/avrjtagicev2
+
+  - Get an avrdude.conf which supports jtag2updi:
+
+    - Download avrdude.conf from https://github.com/ElTangas/jtag2updi
+      and put it in /etc
+
+    - Or grab the source and set an environment variable:
+
+      cd ~/src/torches/avrdude
+      git clone https://github.com/ElTangas/jtag2updi
+      export AVRDUDE_CONF="-C$HOME/src/torches/avrdude/jtag2updi/avrdude.conf"
+
+  - Maybe configure which USB serial port to use too:
+    export AVRDUDE_TTYUSB="/dev/ttyUSB2"
+
+Afterward, flashing should work.  You may need to unplug and replug the jtag2
+USB device between uses though, since it may stop responding after each use.
diff --git a/bin/flash-tiny1616.sh b/bin/flash-tiny1616.sh
index 31c8406..44d716c 100755
--- a/bin/flash-tiny1616.sh
+++ b/bin/flash-tiny1616.sh
@@ -1,3 +1,14 @@
 #/bin/sh
 FIRMWARE=$1
-avrdude -c jtag2updi -P /dev/ttyUSB0 -p t1616 -u -Uflash:w:$FIRMWARE
\ No newline at end of file
+if [ -z "$AVRDUDE_TTYUSB" ]; then AVRDUDE_TTYUSB=/dev/ttyUSB0 ; fi
+
+# In your shell config:
+# from https://github.com/ElTangas/jtag2updi ...
+# export AVRDUDE_CONF="-C$HOME/path/to/jtag2updi/avrdude.conf"
+# export AVRDUDE_TTYUSB="/dev/ttyUSB2"
+
+avrdude $AVRDUDE_CONF \
+  -c jtag2updi \
+  -P $AVRDUDE_TTYUSB \
+  -p t1616 \
+  -u -Uflash:w:$FIRMWARE
-- 
cgit v1.2.3