2025-09-24  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (set_tarpm): reduced vertical tunnel tarpm
	threshold from 57 to 54 in order to suppress 4/3 harmonic locking.

2025-09-23  Aubrey Jaffer  <agj@alum.mit.edu>

	* logger.c (logger_main): raised Tbse from 36.C to 37.C.

	* tick_handler.c (HAL_SYSTICK_Callback): Double tarpm if switches < 105
	and fans_rpm < switches/2.  Locks reliably at 42 rpm in 6 seconds!
	Moved fan_rpm = code earlier in 0==ticnt section.

2025-04-07  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (set_tarpm): 3rd harmonic locking only for
	vertical.
	(line_120_callback): clear bldtim if tarpm < 30; fan still fails
	to cleanly shut down when disabled at start of run.

2025-03-07  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (set_tarpm):
	3rd harmonic extends vertical wind-tunnel range down to 42.r/min.
	Tested only in vertical wind-tunnel.

	* logger.c (logger_main): Don't increment secnt if finished.
	(reached_temp): Extend settling time for first 2 periods.

2024-01-24  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (umph): added.
	(set_tarpm): umph is the orientation dependent coefficient.
	(HAL_SYSTICK_Callback): set umph depending on GPIOB_PIN_2.
	Set switch 1 on for vertical tunnel.

2024-01-11  Aubrey Jaffer  <agj@alum.mit.edu>

	* main.c (MX_GPIO_Init): Changed PB2 on J1p24, PB10 on J1p34
	into pulled up inputs.
	HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_2) from switch 1.
	HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_10) from switch 2.

2023-06-24  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (HAL_SYSTICK_Callback): Fixed rpm calculation
	vulnerability to frequent interrupts; was causing higher speeds to
	undercount.

2023-06-23  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (set_tarpm): Increased limiting rpm 3000-->3500;
	improved stability at 1400 r/min.

2023-06-22  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (line_120_callback): Removed old phase-lock code;
	use sawtooth method above 210.r/min.

2023-06-20  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (line_120_callback): Unified variables saw_blades
	and seen_blades.
	(line_120_callback): Removed binary-rate-multiplier method; was
	not as stable as sawtooth method.

	* stm32f3xx_it.c (COMP4_5_6_IRQHandler): Corrected interrupt
	dispatch.

2023-06-14  Aubrey Jaffer  <agj@alum.mit.edu>

	* stm32f3xx_it.c (COMP4_5_6_IRQHandler): Added COMP5.

	* stm32f3xx_hal_msp.c (HAL_COMP_MspInit, HAL_COMP_MspDeInit):
	Added comp5.

	* main.c (MX_COMP5_Init, MX_GPIO_Init): Use COMP5 (pin PB13) for
	120 Hz interrupt.

	* logger.c (logger_main): HAL_COMP_Start_IT(&hcomp5);

	* tick_handler.c (HAL_SYSTICK_Callback): Split PLL among 4
	methods.

2023-05-25  Aubrey Jaffer  <agj@alum.mit.edu>

	* tick_handler.c (HAL_SYSTICK_Callback): Lengthened sawtooth by
	50%; somewhat more stable, but slower to respond to speed changes.

2022-07-03  Aubrey Jaffer  <agj@alum.mit.edu>
	* tick_handler.c (HAL_SYSTICK_Callback): Reduced cross-section for
	missing a fan blade interrupt.  Had no effect on top fan speed.

2022-06-22  Aubrey Jaffer  <agj@alum.mit.edu>
	* tick_handler.c: restored fan idle.

2022-06-20  Aubrey Jaffer  <agj@alum.mit.edu>
	* tick_handler.c: increased PLL range to 500 (from 399) rpm.
	* tick_handler.c: restored sirpm40 -= 12.

2022-06-12  Aubrey Jaffer  <agj@alum.mit.edu>
	* tick_handler.c bearing has slightly less friction? sirpm40 -= 11.
	* tick_handler.c Disabled fan idle

2022-05-23  Aubrey Jaffer  <agj@alum.mit.edu>
	* tick_handler.c Idle fan at 60.r/min during heating.
	* tick_handler.c: Recompiled for horizontal operation.

2016-04-02  Aubrey Jaffer  <agj@alum.mit.edu>
	* Order of 7-segment anode outputs PD0 - PD7 was reversed.

The STM32F3 spec sheet says that PC13 should not be used to drive leds.
PC6 - PC9 changed from input with pullup to output.
PC10 - PC13 changed from output to input with pullup.
