From 86f82dd02db577cd658ca4284cae15e9664db0f2 Mon Sep 17 00:00:00 2001
From: tmk <hasu@tmk-kbd.com>
Date: Wed, 3 Dec 2014 14:22:10 +0900
Subject: [PATCH] Add wait for charging capacitance of ADC S/H

---
 keyboard/hhkb_rn42/rn42/battery.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/keyboard/hhkb_rn42/rn42/battery.c b/keyboard/hhkb_rn42/rn42/battery.c
index 34aa184..7e868c9 100644
--- a/keyboard/hhkb_rn42/rn42/battery.c
+++ b/keyboard/hhkb_rn42/rn42/battery.c
@@ -92,6 +92,7 @@ uint16_t battery_voltage(void)
 
     volatile uint16_t bat;
     ADCSRA |= (1<<ADEN);
+    _delay_ms(1);   // wait for charging S/H capacitance
 
     ADCSRA |= (1<<ADSC);
     while (ADCSRA & (1<<ADSC)) ;