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/*
* Copyright 2020 Daniel Friesel
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "driver/i2c.h"
#include "arch.h"
#include <msp430.h>
#ifndef F_I2C
#define F_I2C 100000
#endif
volatile unsigned short old_ifg = 0;
#if (F_CPU / F_I2C) < 45
inline void await_i2c_int(unsigned int ie_flags, unsigned int ifg_flags) {
while (!(UCB0IFG & ifg_flags)) ;
if (UCB0IFG & (UCNACKIFG | UCCLTOIFG)) {
UCB0IFG &= ~(UCNACKIFG | UCCLTOIFG);
}
}
#else
inline void await_i2c_int(unsigned int ie_flags, unsigned int ifg_flags)
{
UCB0IFG = 0;
old_ifg = 0;
UCB0IE = ie_flags;
do {
arch.idle();
} while (!(old_ifg & ifg_flags));
UCB0IE = 0;
}
#endif
signed char I2C::setup()
{
#ifdef I2C_PULLUP_FIXED_GPIO
P1DIR |= BIT4 | BIT5;
P1OUT |= BIT4 | BIT5;
#endif
UCB0CTL1 = UCSWRST;
UCB0CTLW0 = UCMODE_3 | UCMST | UCSYNC | UCSSEL_2 | UCSWRST | UCCLTO_1;
UCB0BRW = (F_CPU / F_I2C) - 1;
P1DIR &= ~(BIT6 | BIT7);
P1SEL0 &= ~(BIT6 | BIT7);
P1SEL1 |= BIT6 | BIT7;
UCB0CTL1 &= ~UCSWRST;
UCB0I2CSA = 0;
arch.delay_us(100);
if (UCB0STAT & UCBBUSY)
return -1;
return 0;
}
void I2C::scan(unsigned int *results)
{
for (unsigned char address = 0; address < 128; address++) {
UCB0I2CSA = address;
UCB0CTL1 |= UCTR | UCTXSTT | UCTXSTP;
while (UCB0CTL1 & UCTXSTP);
if (UCB0IFG & UCNACKIFG) {
UCB0IFG &= ~UCNACKIFG;
} else {
results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));
}
}
UCB0IFG = 0;
}
signed char I2C::xmit(unsigned char address,
unsigned char tx_len, unsigned char *tx_buf,
unsigned char rx_len, unsigned char *rx_buf)
{
unsigned char i;
UCB0I2CSA = address;
if (tx_len) {
UCB0CTL1 |= UCTR | UCTXSTT;
for (i = 0; i < tx_len; i++) {
await_i2c_int(UCTXIE0 | UCNACKIE | UCCLTOIE, UCTXIFG0 | UCNACKIFG | UCCLTOIFG);
if (old_ifg & (UCNACKIFG | UCCLTOIFG)) {
UCB0CTL1 |= UCTXSTP;
return -1;
}
old_ifg = 0;
UCB0TXBUF = tx_buf[i];
}
await_i2c_int(UCTXIE0 | UCNACKIE | UCCLTOIE, UCTXIFG0 | UCNACKIFG | UCCLTOIFG);
//if (UCB0IFG & (UCNACKIFG | UCCLTOIFG)) {
// UCB0IFG &= ~UCNACKIFG;
// UCB0IFG &= ~UCCLTOIFG;
// UCB0CTL1 |= UCTXSTP;
// return -1;
//}
}
if (rx_len) {
UCB0I2CSA = address;
UCB0IFG = 0;
UCB0CTL1 &= ~UCTR;
UCB0CTL1 |= UCTXSTT;
while (UCB0CTL1 & UCTXSTT);
UCB0IFG &= ~UCTXIFG0;
for (i = 0; i < rx_len; i++) {
if (i == rx_len - 1)
UCB0CTL1 |= UCTXSTP;
await_i2c_int(UCRXIE | UCNACKIE | UCCLTOIE, UCRXIFG0 | UCNACKIFG | UCCLTOIFG);
rx_buf[i] = UCB0RXBUF;
UCB0IFG &= ~UCRXIFG0;
}
UCB0IFG &= ~UCRXIFG0;
}
UCB0CTL1 |= UCTXSTP;
while (UCB0CTL1 & UCTXSTP);
return 0;
}
__attribute__((interrupt(USCI_B0_VECTOR))) __attribute__((wakeup)) void handle_usci_b0()
{
old_ifg = UCB0IFG;
UCB0IFG = 0;
}
I2C i2c;
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