usb_hw.h

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#ifndef _USB_HW_H_
#define _USB_HW_H_
 
#ifdef __cplusplus
extern "C"{
#endif
 
#include "mcu.h"
#include <stdint.h>
 
#define analog_function_enable(_reg,_pin) (_reg |= 1U << _pin)
 
#define alternate_function_enable(_pin) (GPIO_PORTB_AHB_AFSEL_R |= 1U << _pin)
 
#define GPIO_PORTB_PIN0 (0)
#define GPIO_PORTB_PIN1 (1)
#define GPIO_PORTL_PIN6 (6)
#define GPIO_PORTL_PIN7 (7)
#define USB_DP_PIN GPIO_PORTL_PIN6
#define USB_DN_PIN GPIO_PORTL_PIN7
#define USB_ID_PIN GPIO_PORTB_PIN0
#define USB_VBUS_PIN GPIO_PORTB_PIN1
 
static const unsigned long assumed_mosc_value = 25;
 
static unsigned long get_vco_in_mhz(void){
    unsigned long result = 480;
    const unsigned long sysctl_rsclkcfg_pllsrc24_mask = (0xFUL << 24),
                        mfrac = (SYSCTL_PLLFREQ0_R >> 10) & 0x3FF,
                        mint = SYSCTL_PLLFREQ0_R & 0x3FF,
                        q = (SYSCTL_PLLFREQ1_R >> 8) & 0x1F,
                        n = SYSCTL_PLLFREQ1_R & 0x1F;
 
    if ( SYSCTL_RSCLKCFG_R & SYSCTL_RSCLKCFG_USEPLL ){
        if ( ( SYSCTL_RSCLKCFG_R & sysctl_rsclkcfg_pllsrc24_mask ) == 0 ) {
            result = ( 16 * ( mint + ( mfrac / 1024 ) ) ) / ( ( q + 1 ) * ( n + 1 ) );
        } else if ( ( SYSCTL_RSCLKCFG_R & sysctl_rsclkcfg_pllsrc24_mask ) == ( 3UL << 24 ) ) {
            result = ( assumed_mosc_value * ( mint + ( mfrac / 1024 ) ) ) / ( ( q + 1 ) * ( n + 1 ) );
        }
    }
 
    return result;
}
 
static void usb_set_cc(void){
    unsigned long reg = USB0_CC_R,
                  clkdiv = (get_vco_in_mhz() / 60 - 1);
 
    reg &= ~(0xFUL | USB_CC_CSD);
    reg |= (clkdiv & 0xF) | USB_CC_CLKEN;
 
    USB0_CC_R = reg;
}
 
static inline void usb_hw_init(void) {
    // Enable clock to USB0ID/USB0VBUS pins.
    SYSCTL_RCGCGPIO_R |= SYSCTL_RCGCGPIO_R1;
    // Enable clock to DP/DM pins.
    SYSCTL_RCGCGPIO_R |= SYSCTL_RCGCGPIO_R10;
    // Set pins as analog.
    // The analog functions of the pins are enabled, the isolation is
    // disabled, and the pins are capable of analog functions.
    analog_function_enable(GPIO_PORTB_AHB_AMSEL_R,GPIO_PORTB_PIN0);
    analog_function_enable(GPIO_PORTB_AHB_AMSEL_R,GPIO_PORTB_PIN1);
    // Set pins alternate function.
    // The associated pin functions as a peripheral signal and is
    // controlled by the alternate hardware function.
    alternate_function_enable(GPIO_PORTB_PIN0);
    alternate_function_enable(GPIO_PORTB_PIN1);
    // Set pins as analog.
    // The analog functions of the pins are enabled, the isolation is
    // disabled, and the pins are capable of analog functions.
    analog_function_enable(GPIO_PORTL_AMSEL_R,USB_DN_PIN);
    analog_function_enable(GPIO_PORTL_AMSEL_R,USB_DP_PIN);
    // Enable general USB clock.
    SYSCTL_RCGCUSB_R |= SYSCTL_RCGCUSB_R0;
    // Calculate and set apprpriate USB clock values.
    usb_set_cc();
}
 
 // usb
 // middleware
 
#ifdef __cplusplus
}
#endif
 
#endif // _USB_HW_H_
// ------------------------------------------------------------------------- END