summaryrefslogtreecommitdiff
path: root/src/arch/msp430fr5994lp/driver/i2c.cc
blob: b1ca5fc110e8a216fc2e67e8fcee2c615f7783c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
/*
 * 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 (!(UCB1IFG & ifg_flags)) ;
	if (UCB1IFG & (UCNACKIFG | UCCLTOIFG)) {
		UCB1IFG &= ~(UCNACKIFG | UCCLTOIFG);
	}
}
#else
inline void await_i2c_int(unsigned int ie_flags, unsigned int ifg_flags)
{
	UCB1IFG = 0;
	old_ifg = 0;
	UCB1IE = ie_flags;
	do {
		arch.idle();
	} while (!(old_ifg & ifg_flags));
	UCB1IE = 0;
}
#endif

signed char I2C::setup()
{
#ifdef CONFIG_I2C_PULLUP_FIXED_GPIO
	P8DIR |= BIT2 | BIT3;
	P8OUT |= BIT2 | BIT3;
#endif
	UCB1CTL1 = UCSWRST;
	UCB1CTLW0 = UCMODE_3 | UCMST | UCSYNC | UCSSEL_2 | UCSWRST | UCCLTO_1;
	UCB1BRW = (F_CPU / F_I2C) - 1;
	P5DIR &= ~(BIT0 | BIT1);
	P5SEL0 |= (BIT0 | BIT1);
	P5SEL1 &= ~(BIT0 | BIT1);

	UCB1CTL1 &= ~UCSWRST;
	UCB1I2CSA = 0;

	arch.delay_us(100);

	if (UCB1STAT & UCBBUSY)
		return -1;

	return 0;
}

void I2C::scan(unsigned int *results)
{
	for (unsigned char address = 0; address < 128; address++) {
		UCB1I2CSA = address;
		UCB1CTL1 |= UCTR | UCTXSTT | UCTXSTP;

		while (UCB1CTL1 & UCTXSTP);

		if (UCB1IFG & UCNACKIFG) {
			UCB1IFG &= ~UCNACKIFG;
		} else {
			results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));
		}
	}
	UCB1IFG = 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;
	UCB1I2CSA = address;
	if (tx_len) {
		UCB1CTL1 |= UCTR | UCTXSTT;
		for (i = 0; i < tx_len; i++) {
			await_i2c_int(UCTXIE0 | UCNACKIE | UCCLTOIE, UCTXIFG0 | UCNACKIFG | UCCLTOIFG);
			if (old_ifg & (UCNACKIFG | UCCLTOIFG)) {
				UCB1CTL1 |= UCTXSTP;
				return -1;
			}
			old_ifg = 0;
			UCB1TXBUF = tx_buf[i];
		}
		await_i2c_int(UCTXIE0 | UCNACKIE | UCCLTOIE, UCTXIFG0 | UCNACKIFG | UCCLTOIFG);
		//if (UCB1IFG & (UCNACKIFG | UCCLTOIFG)) {
		//	UCB1IFG &= ~UCNACKIFG;
		//	UCB1IFG &= ~UCCLTOIFG;
		//	UCB1CTL1 |= UCTXSTP;
		//	return -1;
		//}
	}
	if (rx_len) {
		UCB1I2CSA = address;
		UCB1IFG = 0;
		UCB1CTL1 &= ~UCTR;
		UCB1CTL1 |= UCTXSTT;

		while (UCB1CTL1 & UCTXSTT);
		UCB1IFG &= ~UCTXIFG0;

		for (i = 0; i < rx_len; i++) {
			if (i == rx_len - 1)
				UCB1CTL1 |= UCTXSTP;
			await_i2c_int(UCRXIE | UCNACKIE | UCCLTOIE, UCRXIFG0 | UCNACKIFG | UCCLTOIFG);
			rx_buf[i] = UCB1RXBUF;
			UCB1IFG &= ~UCRXIFG0;
		}
		UCB1IFG &= ~UCRXIFG0;
	}

	UCB1CTL1 |= UCTXSTP;

	while (UCB1CTL1 & UCTXSTP);
	return 0;
}

__attribute__((interrupt(USCI_B1_VECTOR))) __attribute__((wakeup)) void handle_usci_b1()
{
	old_ifg = UCB1IFG;
	UCB1IFG = 0;
}

I2C i2c;