From ce2a2e98b5f8b59cd358b5681348a0b450a468d6 Mon Sep 17 00:00:00 2001
From: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Date: Wed, 20 Jul 2022 19:19:45 -0400
Subject: [PATCH] Create a power management/battery management prototype

---
 flake.nix               | 31 +++++++++++++++++++++++++++++++
 power-management/main.c | 20 ++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 power-management/main.c

diff --git a/flake.nix b/flake.nix
index 10056ca..523269d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -387,6 +387,37 @@
             '';
         };
 
+      packages."x86_64-linux"."power-management-standalone" = (packages."x86_64-linux"."power-management" attiny85);
+
+      packages."x86_64-linux"."power-management" =
+        { mcu, chip_select, f_cpu }:
+        let
+          pkgs = import nixpkgs { system = "x86_64-linux"; };
+          lib = pkgs.lib;
+          avr = pkgs.pkgsCross.avr.buildPackages;
+        in pkgs.stdenv.mkDerivation rec {
+          name = "power-management";
+          src = ./.;
+
+          buildInputs = [
+            (packages."x86_64-linux"."base" { inherit mcu chip_select f_cpu; })
+          ];
+
+          CFLAGS = cflags { inherit mcu chip_select f_cpu; };
+          INCLUDE_DIRS = pkgs.lib.concatStringsSep " " (map (dir: "-I${dir}") buildInputs);
+          OBJECT_FILES = pkgs.lib.concatStringsSep " " (map (dir: "${dir}/*.o") buildInputs);
+
+          buildPhase = ''
+            ${avr.gcc}/bin/avr-gcc ${CFLAGS} ${INCLUDE_DIRS} -o main.o -c ${src}/power-management/main.c
+            ${avr.gcc}/bin/avr-gcc ${CFLAGS} -o power-management.elf main.o ${OBJECT_FILES}
+            $OBJCOPY -O ihex power-management.elf power-management.hex
+            '';
+          installPhase = ''
+            mkdir $out
+            cp power-management.elf power-management.hex $out
+            '';
+        };
+
       devShell."x86_64-linux" =
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
diff --git a/power-management/main.c b/power-management/main.c
new file mode 100644
index 0000000..ec56e57
--- /dev/null
+++ b/power-management/main.c
@@ -0,0 +1,20 @@
+#include <base.h>
+
+#define TIMEOUT 1
+
+int main(void) {
+    dio_t power = { .ddr = &DDRB, .pin = &PINB, .port = &PORTB, .addr = 3 };
+    dio_set_direction(&power, LINE_OUT);
+
+    int timeout_seconds = TIMEOUT;
+    while (1) {
+        if (timeout_seconds <= 0) {
+            dio_set(&power, 1);
+            _delay_ms(50);
+            dio_set(&power, 0);
+            timeout_seconds = TIMEOUT;
+        }
+        timeout_seconds--;
+        _delay_ms(1000);
+    }
+}