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Commit c3db53c

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made i2c functions much more simple, modular, and faster. Now will test them inside the rtos tasks.
1 parent d769f53 commit c3db53c

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4 files changed

+63
-66
lines changed

4 files changed

+63
-66
lines changed

‎include/i2c.h‎

Lines changed: 3 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -26,17 +26,14 @@ Date: 12/30/2024
2626
#define TSL2591_DATA_REGISTER (0xB4U)
2727
#define TSL2591_INIT_MESSAGE ((0xA0 << 8)|(0x03))
2828

29-
//timing for 16MHz I2CCLK and 100KHz transmission frequency
30-
//#define I2C2_TIMING_VALS ((0x3<<28)|(0x4<<20)|(0x2<<16)|(0xF<<8)|(0x13))
29+
#define I2C2_NBYTES (4U)
3130

3231
//timing for 16MHz I2CCLK and 400KHz transmission frequency
3332
#define I2C2_TIMING_VALS ((0x1<<28)|(0x3<<20)|(0x2<<16)|(0x3<<8)|(0x9))
3433

3534
void i2c2_init(void);
36-
void i2c2_write(uint8_t NBYTES, const uint16_t w_buffer);
37-
void i2c2_write_read(uint8_tNBYTES, const uint16_ttarget_reg, uint32_t*r_buffer);
35+
void i2c2_write(constuint8_t NBYTES, const uint16_t w_buffer);
36+
void i2c2_read(const uint8_tNBYTES);
3837
uint8_t i2c2_check_bus(void);
39-
void i2c2_resolve_deadlock(void);
40-
void I2C2_EV_IRQHandler(void);
4138

4239
#endif /* I2C_H */

‎src/i2c.c‎

Lines changed: 49 additions & 50 deletions
Original file line numberDiff line numberDiff line change
@@ -14,12 +14,15 @@ Purpose: configure I2C2 and implement read and write functions
1414
#include "nvic.h"
1515
#include "tcnt.h"
1616

17+
volatile uint8_t g_i2c2_rx_count = 0;
18+
extern volatile uint32_t g_read_buffer;
19+
1720
//initialize I2C2 registers: 100KHz SCL Frequency, 7-bit addressing mode
1821
void i2c2_init(void) {
1922
gpio_i2c2_init(); //set up gpio for i2c2
2023

2124
I2C2_CR1 &= ~1; //disable I2C2 Peripheral
22-
I2C2_CR1 |= (1 << 4); //enable NACK interrupt
25+
I2C2_CR1 |= (1 << 2); //enable receive interrupt
2326

2427
I2C2_TIMINGR |= I2C2_TIMING_VALS;
2528

@@ -28,75 +31,49 @@ void i2c2_init(void) {
2831
}
2932

3033
//write to the target; this function only allows up to 2 bytes of data transmission at once
31-
void i2c2_write(uint8_t NBYTES, const uint16_t w_buffer) {
34+
void i2c2_write(constuint8_t NBYTES, const uint16_t w_buffer) {
3235
I2C2_CR2 &= ~(1 << 10); //set to Write
3336
I2C2_CR2 &= ~(0xFF << 16); //clear NBYTES; if this is not done then sometimes no stop condition
3437
I2C2_CR2 |= (NBYTES << 16); //NBYTES = NBYTES parameter
3538

36-
//loop until bus is idle
3739
volatile int count = 0;
3840
uint8_t timeout = 0xFF;
39-
while (timeout != 1) timeout = i2c2_check_bus();
41+
while (timeout != 1) { //loop until bus is idle
42+
timeout = i2c2_check_bus();
43+
}
4044

4145
I2C2_CR2 |= (1 << 13); //send start condition
4246

4347
//loop until all bytes are sent
4448
for (count = NBYTES-1; count > -1; count--) {
4549
while (!((I2C2_ISR >> 1) & 1)); //loop until TXIS flag is set
46-
I2C2_TXDR = (uint8_t)((w_buffer >> (8*count)) &0xFF);
50+
I2C2_TXDR = (uint8_t) (w_buffer >> (8*count));
4751
}
4852

49-
//delay for target device to process 2nd data byte
50-
timer3_delay_us(500);
53+
if (NBYTES > 1) {
54+
timer3_delay_us(30); //delay for target device to process 2nd data byte
55+
}
5156

5257
I2C2_CR2 |= (1 << 14); //send STOP condition
5358
I2C2_ICR |= (1 << 5); //clear stop flag
5459
}
5560

56-
//Write to a register in the target device then read and store 4 bytes to the r_buffer
57-
void i2c2_write_read(uint8_t NBYTES, const uint16_t target_reg, uint32_t *r_buffer) {
58-
*r_buffer = 0; //clear r_buffer
59-
60-
//complete write section first:
61-
I2C2_CR2 &= ~(1 << 10); //set to Write
62-
I2C2_CR2 &= ~(0xFF << 16); //clear NBYTES; if this is not done then sometimes no stop condition
63-
I2C2_CR2 |= (1 << 16); //NBYTES = 1
64-
65-
//loop until bus is idle
66-
volatile int count = 0;
67-
uint8_t timeout = 0xFF;
68-
while (timeout != 1) timeout = i2c2_check_bus();
69-
70-
I2C2_CR2 |= (1 << 13); //send start condition
71-
72-
while (!((I2C2_ISR >> 1) & 1)); //loop until TXIS flag is set
73-
I2C2_TXDR = target_reg & 0xFF; //only use first byte
74-
75-
//repeated START to do read section:
76-
while ((I2C2_CR2 >> 13) & 1); //loop until START bit is not set
77-
61+
//read from the i2c bus
62+
void i2c2_read(const uint8_t NBYTES) {
7863
I2C2_CR2 |= (1 << 10); //set to Read
7964
I2C2_CR2 &= ~(0xFF << 16); //clear NBYTES; if this is not done then sometimes no stop condition
8065
I2C2_CR2 |= (NBYTES << 16); //NBYTES = 4 for the TSL2591 data registers
8166

82-
//loop until bus is idle
83-
count = 0;
84-
timeout = 0xFF;
85-
while (timeout != 1) timeout = i2c2_check_bus();
67+
volatile int count = 0;
68+
uint8_t timeout = 0xFF;
69+
while (timeout != 1) { //loop until bus is idle
70+
timeout = i2c2_check_bus();
71+
}
8672

8773
I2C2_CR2 |= (1 << 13); //send start condition
8874

89-
//loop until all bytes are read
90-
for (count = 0; count < NBYTES; count++) {
91-
while (!((I2C2_ISR >> 2) & 1)); //loop until RXNE flag is set
92-
*r_buffer |= (I2C2_RXDR & 0xFF) << (count*8);
93-
}
94-
95-
//NOTE: NACK is automatically sent after the last byte reception.
96-
97-
I2C2_CR2 |= (1 << 14); //send STOP condition
98-
I2C2_ICR |= (1 << 5); //clear stop flag
99-
}
75+
g_read_buffer = 0;
76+
}
10077

10178
//Use timers to check if the bus goes idle; returns 1 if idle and 0 if not idle
10279
uint8_t i2c2_check_bus(void) {
@@ -118,14 +95,36 @@ uint8_t i2c2_check_bus(void) {
11895
}
11996
}
12097

121-
//Function to resolve I2C deadlocks - not completed
122-
void i2c2_resolve_deadlock(void) {
123-
}
124-
125-
//IRQ handler for I2C2 event interrupts; for now for NACKs
98+
//IRQ handler for I2C2 event interrupts - for receives!
12699
void I2C2_EV_IRQHandler(void) {
127100
nvic_disable();
128-
//do something
101+
102+
static uint8_t bytes_rx; //holds number of bytes received
103+
104+
//if this is the first received byte, init a count var to 1
105+
if (g_i2c2_rx_count == 0) {
106+
///*
107+
bytes_rx = 0;
108+
g_read_buffer |= ((uint8_t) I2C2_RXDR) << (g_i2c2_rx_count*8);
109+
//*/
110+
111+
bytes_rx = 1;
112+
g_i2c2_rx_count = 1;
113+
}
114+
else {
115+
///*
116+
g_read_buffer |= ((uint8_t) I2C2_RXDR) << (bytes_rx*8);
117+
//*/
118+
119+
bytes_rx++;
120+
}
121+
122+
if (bytes_rx == I2C2_NBYTES) {
123+
I2C2_CR2 |= (1 << 14); //send STOP condition
124+
I2C2_ICR |= (1 << 5); //clear stop flag
125+
bytes_rx = 0;
126+
g_i2c2_rx_count = 0;
127+
}
129128
nvic_enable();
130129
}
131130

‎src/main.c‎

Lines changed: 6 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -27,6 +27,7 @@ Purpose: To get the LD2 on the Nucleo-L476RG to turn on.
2727
extern volatile uint8_t global_button_flag;
2828

2929
volatile uint32_t lux_data;
30+
volatile uint32_t g_read_buffer = 0;
3031

3132
//task prototypes
3233
void task1_handler(void *args); //handles comms with lux sensor
@@ -57,10 +58,11 @@ static void hardware_init(void) {
5758
i2c2_write(2, TSL2591_INIT_MESSAGE);
5859
tsl2591_write_settings(again_low, atime_100ms);
5960

60-
uint32_t raw_data;
61-
i2c2_write_read(4, TSL2591_DATA_REGISTER, &raw_data);
62-
lux_data = rawdata_to_lux(raw_data, again_low, atime_100ms);
61+
i2c2_write(1, TSL2591_DATA_REGISTER);
62+
i2c2_read(4);
6363

64+
timer3_delay_us(50000);
65+
lux_data = rawdata_to_lux(g_read_buffer, again_low, atime_100ms);
6466

6567
char lux_buf[] = " "; //init an empty buffer for lux measurements. -> has size [15] (added null term)
6668
snprintf(lux_buf, 15, "%lu ", lux_data);
@@ -72,7 +74,6 @@ static void hardware_init(void) {
7274
lcd_text_buffer_t lux_text_buffer = {lux_buf};
7375

7476
lcd_output_text(lux_text_buffer);
75-
7677
}
7778

7879
int main(void) {
@@ -107,7 +108,7 @@ void task1_handler(void *args) {
107108
while(1) {
108109
/*
109110
gpio_led_on();
110-
i2c2_write_read(4, TSL2591_DATA_REGISTER, &raw_data);
111+
i2c2_write_read(4, TSL2591_DATA_REGISTER);
111112
lux_data = rawdata_to_lux(raw_data, again_low, atime_100ms);
112113
*/
113114
}

‎src/nvic.c‎

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -11,21 +11,21 @@ Purpose: To control interrupts through the NVIC;
1111
//enable NVIC
1212
void nvic_enable(void) {
1313
NVIC_ISER1 |= (1 << 8); //enable interrupt 40 (user button)
14+
NVIC_ISER1 |= (1 << 1); //enable interrupt 33 (I2C2_EV)
1415
//NVIC_ISER0 |= (1 << 28); //enable interrupt 28 (TIM2 global interrupt)
1516
}
1617

1718
//disable NVIC
1819
void nvic_disable(void) {
1920
NVIC_ICER1 |= (1 << 8); //disable interrupt 40 (user button)
21+
NVIC_ICER1 |= (1 << 1); //disable interrupt 33 (I2C2_EV)
2022
//NVIC_ICER0 |= (1 << 28); //disable interrupt 28 (TIM2 global interrupt)
2123
}
2224

2325
//change priorities of nvic
2426
void nvic_priority(void) {
25-
//change priority of button interrupt (40) to lowest
26-
NVIC_IPR10 |= (0xF << 4);
27-
//change priority of TIM2 global interrupt (28) to lowest
28-
//NVIC_IPR7 |= (0xF << 0);
29-
27+
NVIC_IPR10 |= (0xF << 4); //change priority of button interrupt (40) to lowest
28+
NVIC_IPR8 |= (0xE << 12); //change priority of I2C2 receive interrupt (33) to second lowest
29+
//NVIC_IPR7 |= (0xF << 0); //change priority of TIM2 global interrupt (28) to lowest
3030
}
3131

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