got ADC voltage+temp working on avrdd... but broke all other builds/MCUs

This patch changes the ADC code to use two internal standard units, and
everything else must convert to these units:

- FSM Volts: centiVolts << 6  (range 0 to 10.24 V per cell)
- FSM Kelvin: Kelvin << 6  (range 0 to 1024 K)

UI-level voltage is still "Volts * 10", and temperature is still Celsius.

FSM expects functions to be provided, to convert from the hardware's
raw ADC measurements to these internal units:  `voltage_raw2cooked()`
and `temp_raw2cooked()`.  Defaults will be provided by arch/*.[ch] for
each MCU type, or the hwdef can make its own.

Anyway, gotta go fix all the other MCUs and builds now.  :(

2 files changed, 22 insertions, 3 deletions

diff --git a/hw/thefreeman/avr32dd20-devkit/hwdef.c b/hw/thefreeman/avr32dd20-devkit/hwdef.c
index e5b347f..133baca 100644
--- a/hw/thefreeman/avr32dd20-devkit/hwdef.c
+++ b/hw/thefreeman/avr32dd20-devkit/hwdef.c
@@ -103,3 +103,16 @@ bool gradual_tick_main(uint8_t gt) {
     return false;  // not done yet
 }
 
+
+uint16_t voltage_raw2cooked(uint16_t measurement) {
+    // In : 65535 * BATTLVL pin / 1.024 Vref
+    // Out: 65535 * (Vbat / 10) / 1.024V  (i.e. FSM Volt units)
+    // BATTLVL = Vbat * (100.0/(330+100)) = Vbat / 4.3
+    // So, Out = In * 4.3 / 10.24
+    // (plus 1.5% based on measured hardware)
+    // (plus a fudge factor of +0.04V to round up to nearest 1/10th Volt)
+    uint16_t result = ((uint32_t)measurement * 436 / 1024)
+                    + (65535 * 4 / 1024);
+    return result;
+}
+
diff --git a/hw/thefreeman/avr32dd20-devkit/hwdef.h b/hw/thefreeman/avr32dd20-devkit/hwdef.h
index 7e093f9..7e1ad3d 100644
--- a/hw/thefreeman/avr32dd20-devkit/hwdef.h
+++ b/hw/thefreeman/avr32dd20-devkit/hwdef.h
@@ -35,7 +35,7 @@
  *         and low value Rsense (high current range, pin high)
  * IN- NFET : pull up after BST enable to eliminate startup flash, pull down otherwise
  * CH senses the status of the onboard charger
- * LVL : ??? (unused?)
+ * BATT LVL : Vbat * (100.0/(330+100))
  * LVB is for OTSM firmware, not used here
  */
 
@@ -109,8 +109,14 @@ enum CHANNEL_MODES {
 
 // TODO: define stuff for the voltage divider
 // AVR datasheet table 3.1 I/O Multiplexing, PA6 ADC0 = AIN26
-//#define USE_VOLTAGE_DIVIDER    // use a dedicated pin, not VCC, because VCC input is regulated
+#define USE_VOLTAGE_DIVIDER    // use a dedicated pin, not VCC, because VCC input is regulated
 #define ADMUX_VOLTAGE_DIVIDER  ADC_MUXPOS_AIN26_gc
+#define DUAL_VOLTAGE_FLOOR     21 // for AA/14500 boost drivers, don't indicate low voltage if below this level
+#define DUAL_VOLTAGE_LOW_LOW   7  // the lower voltage range's danger zone 0.7 volts (NiMH)
+// convert BATT LVL pin readings to FSM volt units
+#undef voltage_raw2cooked
+uint16_t voltage_raw2cooked(uint16_t measurement);
+
 
 // average drop across diode on this hardware
 #ifndef VOLTAGE_FUDGE_FACTOR
@@ -148,7 +154,7 @@ inline void hwdef_setup() {
     //PORTA.PIN3CTRL = PORT_PULLUPEN_bm;  // CH
     PORTA.PIN4CTRL = PORT_PULLUPEN_bm;
     PORTA.PIN5CTRL = PORT_PULLUPEN_bm;
-    PORTA.PIN6CTRL = PORT_PULLUPEN_bm;
+    //PORTA.PIN6CTRL = PORT_PULLUPEN_bm;  // BATT LVL
     //PORTA.PIN7CTRL = PORT_PULLUPEN_bm;  // HDR
 
     //PORTC.PIN0CTRL = PORT_PULLUPEN_bm;  // doesn't exist