From baaa035cf93340b8f2c626bdba47e8066cf40067 Mon Sep 17 00:00:00 2001
From: Selene ToyKeeper
Date: Wed, 22 Nov 2023 05:34:26 -0700
Subject: ADC voltage: battcheck 3 digits, fixed t1616, switched back to 8-bit
 internal volt unit

Before this branch, `voltage` was 6 bits: Volts * 10
A couple patches ago, I upgraded it to 16 bits: 65535 * Volts / 10.24
That costs too much extra ROM on attiny85 though, for extra precision
it doesn't even use... so I switched back to an 8-bit value.  It's still
more precise than before though: Volts * 40
... and battcheck displays an extra digit now, on devices with ROM for it.
... and battcheck waits a second to get a more accurate measurement
    before displaying the first value.  It has *much* less variation
    between first and later readings now.

Also:
- got t1616 builds working again (tested fc13 and thefreeman-boost-fwaa)
- upgraded t1616 voltage and temp to 12-bit (10 bits + 4x oversampling)
- removed expensive temp conversion from t1616 ADC interrupt
- recalibrated t1616 bogomips again; runs faster after interrupt fix
- increased t1616 internal VDD measurement resolution by 36% (1.5V Vref, not 1.1V)
- fixed sloppy setting of Vref bits

I still need to test / update other t1616 builds,
and fix all the t85 + t1634 code and build targets.
---
 arch/avr32dd20.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'arch/avr32dd20.h')

diff --git a/arch/avr32dd20.h b/arch/avr32dd20.h
index 3ebb05a..82951de 100644
--- a/arch/avr32dd20.h
+++ b/arch/avr32dd20.h
@@ -58,9 +58,9 @@ inline uint16_t mcu_adc_result();
 //inline uint16_t mcu_adc_result_temp();
 //inline uint16_t mcu_adc_result_volts();
 
-// return (centiVolts << 6), range 0 to 10.24V
+// return Volts * 40, range 0 to 6.375V
 #define voltage_raw2cooked  mcu_vdd_raw2cooked
-inline uint16_t mcu_vdd_raw2cooked(uint16_t measurement);
+inline uint8_t mcu_vdd_raw2cooked(uint16_t measurement);
 
 // return (temp in Kelvin << 6)
 #define temp_raw2cooked  mcu_temp_raw2cooked
-- 
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