#![no_main]
#![no_std]

// MCU is STM32F303VCT6
//
// Which GPIOs are free to use??
// Rather, which are taken? FROM THE DISCOVERY PDF:
// PA0  - AIN_1 with some filtering
// PA2  - STLINK_TX
// PA3  - STLINK_RX
// PA5  - SCL/SPC, T_JTCK
// PA6  - SA0/SDO, T_JTDO
// PA7  - SDA/SDI/SDO, T_JTDI
// PA8  - MCO (with LPF)
// PA9  - maybe tied to PA11
// PA10 - maybe tied to PA12
// PA11 - D-, maybe tied to PA9
// PA12 - D+, maybe tied to PA10
// PA13 - TMS/SWDIO
// PA14 - TCK/SWCLK
// PA15 - JTDI
// PB0  - T_NRST
// PB2  - GND
// PB3  - T_SWO
// PB4  - JNTRST
// PB5  - SWIM_RST_IN
// PB6  - SWIM_RST, SCL
// PB7  - SWIM_IN, SDA
// PB8  - SWIM
// PB9  - SWIM_IN
// PB10 - SWIM_IN
// PB11 - SWIM
// PB12 - T_SWDIO_IN connected to PB14
// PB13 - T_JTCK
// PB14 - T_JTMS connected to PB12
// PC4  - USARTI_RX
// PC5  - USARTI_TX
// PC13 - 10k pulldown
// PC14 - 10k pulldown (not fitted) tied to PC14-OSC32_IN
// PC15 - tied to PC15-OSC32_OUT
// PE0  - INT1
// PE1  - DRDY/INT2
// PE2  - DRDY
// PE3  - CS_I2C/SPI
// PE4  - INT1
// PE5  - INT2
// PE8  - LD4 blue
// PE9  - LD3 red
// PE10 - LD5 orange
// PE11 - LD7 green
// PE12 - LD9 blue
// PE13 - LD10 red
// PE14 - LD8 orange
// PE15 - LD6 green
// PF0  - tied to PF0-OSC_IN
// PF1  - tied to PF1-OSC_OUT
//
// It looks like Port D is safe to use, most of port c  
//
// WHICH PINS CAN BE ROUTED TO THE ADC? (from the device data sheet)
// PA0  - ADC1_IN1
// PA1  - ADC1_IN2
// PA2  - ADC1_IN3
// PA3  - ADC1_IN4
// PA4  - ADC2_IN1
// PA5  - ADC2_IN2
// PA6  - ADC2_IN3
// PA7  - ADC2_IN4
// PB0  - ADC3_IN12
// PB1  - ADC3_IN1
// PB2  - ADC2_IN12
// PB12 - ADC4_IN3
// PB13 - ADC3_IN5
// PB14 - ADC4_IN4
// PB15 - ADC4_IN5
// PC0  - ADC12_IN6
// PC1  - ADC12_IN7
// PC2  - ADC12_IN8
// PC3  - ADC12_IN9
// PC4  - ADC2_IN5
// PC5  - ADC2_IN11
// PD8  - ADC4_IN12
// PD9  - ADC4_IN12
// PD10 - ADC34_IN7
// PD11 - ADC34_IN8
// PD12 - ADC34_IN8
// PD12 - ADC34_IN9
// PD13 - ADC34_IN10
// PD14 - ADC34_IN11
// PE7  - ADC3_IN13
// PE9  - ADC3_IN2
// PE10 - ADC3_IN14
// PE11 - ADC3_IN15
// PE12 - ADC3_IN16
// PE13 - ADC3_IN3
// PE14 - ADC4_IN1
// PE15 - ADC4_IN2
// PF2  - ADC12_IN10
// PF4  - ADC1_IN5
//
// PC0-3 look safe to use as ADC. PF2,4 as well.
//
// ANALOG INPUT
// from 11.3.2:
// For the ADC, DAC, OPAMP, and COMP, configure the desired I/O in analog mode
// in the GPIOx_MODER register and configure the required function in the ADC,
// DAC, OPAMP, and COMP registers.
//
// Need to generate ADC12_CK or ADC34_CK from RCC. Or derived from AHB bus clock. See CKMODE[1:0] of the ADCx_CCR

extern crate panic_itm; // panic handler

mod bsp;

use cortex_m::asm::bkpt;
use cortex_m_rt::entry;

#[entry]
fn main() -> ! {
    let per = bsp::init();

    // Configure clock gates
    per.rcc.ahbenr.modify(|_, w| {
        // enable IO Port A (push-button)
        w.iopaen().enabled();
        // enable IO Pord D (piezo)
        w.iopden().enabled();
        // enable IO Port E (LEDs)
        w.iopeen().enabled();
        // enable ADC 1/2
        w.adc12en().enabled()
    });

    // All LEDS are outputs
    per.gpioe.moder.modify(|_, w| {
        // NB colin: there's also a .analog() mode!
        w.moder8().output();
        w.moder9().output();
        w.moder10().output();
        w.moder11().output();
        w.moder12().output();
        w.moder13().output();
        w.moder14().output();
        w.moder15().output()
    });

    // Configure push-button as input:
    per.gpioa.moder.modify(|_, w| {
        w.moder0().input()
    });

    // Configure piezo as digital input
    per.gpiod.moder.modify(|_, w| {
        w.moder0().input()
    });

    // Turn on all the LEDs in the compass
    per.gpioe.odr.write(|w| {
        w.odr8().set_bit();
        w.odr9().set_bit();
        w.odr10().set_bit();
        w.odr11().set_bit();
        w.odr12().set_bit();
        w.odr13().set_bit();
        w.odr14().set_bit();
        w.odr15().set_bit()
    });

    // Enable the ADC voltage regulator. 15.3.6
    // Note: by default ADC will be clocked off the bus clock, divided by two.
    per.adc1.cr.modify(|_, w| {
        w.deeppwd().clear_bit()
    });
    // Docs make it sound like this _must_ be two separate writes.
    // "T ADCVREG_STUP
    // "The software must wait for the startup time of the ADC voltage regulator
    // (T ADCVREG_STUP ) before launching a calibration or enabling the ADC."
    // 10 uS worst-case
    // TODO: add delay
    per.adc1.cr.modify(|_, w| {
        w.advregen().set_bit()
    });
    // TODO: delay 10 uS before starting cal

    // Calibrate the ADC
    per.adc1.cr.modify(|_, w| {
        w.adcal().set_bit()
    });
    // XXX we should probably loop until adcal is zero again, but meh.
    
    // TODO: set ADEN=1
    // wait for ADRDY=1
    // TODO: configure mux'ing: SQRx, JSQRx
    // TODO: ADSTART=1

    bkpt();

    loop {
        //let push_button = per.gpioa.idr.read().idr0().bit();
        let push_button = per.gpiod.idr.read().idr0().bit();
        per.gpioe.odr.modify(|_, w| {
            w.odr8().bit(push_button)
        });
    }
}