1 files changed, 34 insertions, 2 deletions
diff --git a/keyboards/handwired/promethium/promethium.c b/keyboards/handwired/promethium/promethium.c
index a0035cce1a..62e2281fac 100644
--- a/keyboards/handwired/promethium/promethium.c
+++ b/keyboards/handwired/promethium/promethium.c
@@ -1,6 +1,38 @@
 #include "promethium.h"
+#include "analog.h"
+#include "timer.h"
+#include "matrix.h"
 
-void matrix_init_kb(void) {
+// cubic fit {3.3, 0}, {3.5, 2.9}, {3.6, 5}, {3.7, 8.6}, {3.8, 36},  {3.9, 62}, {4.0, 73}, {4.05, 83}, {4.1, 89}, {4.15, 94}, {4.2, 100}
+
+uint8_t battery_level(void) {
+    float voltage = analogRead(BATTERY_PIN) * 2 * 3.3 / 1024;
+    if (voltage < MIN_VOLTAGE) return 0;
+    if (voltage > MAX_VOLTAGE) return 255;
+    return (voltage - MIN_VOLTAGE) / (MAX_VOLTAGE - MIN_VOLTAGE) * 255;
+}
+
+__attribute__ ((weak))
+void battery_poll(uint8_t level) {
+}
 
+void matrix_init_kb(void) {
 	matrix_init_user();
-}
-\ No newline at end of file
+}
+
+void matrix_scan_kb(void) {
+    static uint16_t counter = BATTERY_POLL;
+    counter++;
+
+    if (counter > BATTERY_POLL) {
+        counter = 0;
+        battery_poll(battery_level());
+    }
+
+    matrix_scan_user();
+}
+
+void led_set_kb(uint8_t usb_led) {
+    led_set_user(usb_led);
+}
+