From 35b5c42f8996167248b7e6d2e4053f6bbef1505c Mon Sep 17 00:00:00 2001
From: Selene ToyKeeper
Date: Tue, 26 Mar 2024 03:41:17 -0600
Subject: d3aa: got weak battery detection actually working, and not letting
 the magic smoke out of updi adapters any more (probably)

The alkaline detection might be a little too lenient though; it
could potentially fail to activate limits when the cell is completely
full or stronger than an average alkaline.  One of my test cells
measured at 72 / 75, so if it was just a little stronger it'd pass...
but most alkalines I tried were in the 40 to 60 range and failed easily.

OTOH, if I make it easier to fail, it's likely to trip on normal li-ion
cells, and I don't want that.

So as a future enhancement idea, maybe it should have a smaller sag
threshold for AA and a larger threshold for li-ion.  That would reduce
false negatives for AA, while still preventing false positives for li-ion.
---
 hw/hank/emisar-d3aa/hwdef.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

(limited to 'hw/hank/emisar-d3aa/hwdef.h')

diff --git a/hw/hank/emisar-d3aa/hwdef.h b/hw/hank/emisar-d3aa/hwdef.h
index 1e677b6..7cd2849 100644
--- a/hw/hank/emisar-d3aa/hwdef.h
+++ b/hw/hank/emisar-d3aa/hwdef.h
@@ -116,12 +116,11 @@ enum CHANNEL_MODES {
 
 // Alkaline AA can't handle the power this light wants,
 // so try to detect it and limit the maximum power
+// (also helps protect firmware flashing adapters from overload)
 #define USE_RAMP_LEVEL_HARD_LIMIT
 #define USE_WEAK_BATTERY_PROTECTION
-#define WEAK_BATTERY_HIGHEST_LIMIT  RAMP_SIZE
-#define WEAK_BATTERY_MEDIUM_LIMIT   (RAMP_SIZE*2/3)
-#define WEAK_BATTERY_LOWEST_LIMIT   (RAMP_SIZE*1/3)
-#define WEAK_BATTERY_CHECK_LEVEL    (RAMP_SIZE*2/3)
+#define WEAK_BATTERY_TEST_MAX_LEVEL 75  // about 300 mA
+#define WEAK_BATTERY_SAG_THRESHOLD  (5*4)  // 0.5 V
 
 // average drop across diode on this hardware
 #ifndef VOLTAGE_FUDGE_FACTOR
-- 
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