serial.c

#include "defines.h"
#include "serial.h"

#define SERIAL_SCI_NUM 3

#define H8_3069F_SCI0 ((volatile struct h8_3069f_sci *)0xffffb0)
#define H8_3069F_SCI1 ((volatile struct h8_3069f_sci *)0xffffb8)
#define H8_3069F_SCI2 ((volatile struct h8_3069f_sci *)0xffffc0)

struct h8_3069f_sci {
    volatile uint8 smr;
    volatile uint8 brr;
    volatile uint8 scr;
    volatile uint8 tdr;
    volatile uint8 ssr;
    volatile uint8 rdr;
    volatile uint8 scmr;
};

#define H8_3069F_SCI_SMR_CKS_PER1  (0<<0)
#define H8_3069F_SCI_SMR_CKS_PER4  (1<<0)
#define H8_3069F_SCI_SMR_CKS_PER16 (2<<0)
#define H8_3069F_SCI_SMR_CKS_PER64 (3<<0)
#define H8_3069F_SCI_SMR_MP        (1<<2)
#define H8_3069F_SCI_SMR_STOP      (1<<3)
#define H8_3069F_SCI_SMR_OE        (1<<4)
#define H8_3069F_SCI_SMR_PE        (1<<5)
#define H8_3069F_SCI_SMR_CHR       (1<<6)
#define H8_3069F_SCI_SMR_CA        (1<<7)

#define H8_3069F_SCI_SCR_CKE0      (1<<0)
#define H8_3069F_SCI_SCR_CKE1      (1<<1)
#define H8_3069F_SCI_SCR_TEIE      (1<<2)
#define H8_3069F_SCI_SCR_MPIE      (1<<3)
#define H8_3069F_SCI_SCR_RE        (1<<4)
#define H8_3069F_SCI_SCR_TE        (1<<5)
#define H8_3069F_SCI_SCR_RIE       (1<<6)
#define H8_3069F_SCI_SCR_TIE       (1<<7)

#define H8_3069F_SCI_SSR_MPBT      (1<<0)
#define H8_3069F_SCI_SSR_MPB       (1<<1)
#define H8_3069F_SCI_SSR_TEND      (1<<2)
#define H8_3069F_SCI_SSR_PER       (1<<3)
#define H8_3069F_SCI_SSR_FERERS    (1<<4)
#define H8_3069F_SCI_SSR_ORER      (1<<5)
#define H8_3069F_SCI_SSR_RDRF      (1<<6)
#define H8_3069F_SCI_SSR_TDRE      (1<<7)

static struct {
    volatile struct h8_3069f_sci *sci;
} regs[SERIAL_SCI_NUM] = {
    { H8_3069F_SCI0 },
    { H8_3069F_SCI1 },
    { H8_3069F_SCI2 },
};

int serial_init(int index)
{
    volatile struct h8_3069f_sci *sci = regs[index].sci;
    
    sci->scr = 0;
    sci->smr = 0;
    sci->brr = 64;
    sci->scr = H8_3069F_SCI_SCR_RE | H8_3069F_SCI_SCR_TE;
    sci->ssr = 0;

    return 0;
}

int serial_is_send_enable(int index)
{
    volatile struct h8_3069f_sci *sci = regs[index].sci;
    return (sci->ssr & H8_3069F_SCI_SSR_TDRE);
}

int serial_send_byte(int index, unsigned char c)
{
    volatile struct h8_3069f_sci *sci = regs[index].sci;

    while (!serial_is_send_enable(index)) {
        ;
    }

    sci->tdr = c;
    sci->ssr &= ~H8_3069F_SCI_SSR_TDRE;

    return 0;
}