42/42_EXT_03_42chips
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

working with delays

Browse Source
This commit is contained in:
hugo LAMY
2025-03-17 09:05:13 +01:00
parent a7dd28c31a
commit e59346adc6
2 changed files with 27 additions and 478 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
module06/ex01/i2c.c
View File

@@ -14,10 +14,6 @@ void i2c_init(void) {
TWBR = ((F_CPU / TWI_FREQ) - 16) / (2 * TWI_PRESCALE_VALUE); // 22.9.1 : (Bit Rate Register) set SCL frequency (formula from datasheet, 22.5.2)
}
void i2c_start_repeat(void) { // 22.7.1 : "Repeated START enables the Master to switch between Slaves, Master Transmitter mode and Master Receiver mode without losing control of the bus"
i2c_start();
}
void i2c_start(void) {
i2c_status = START;
TWCR = TWI_START_CONDITION; // 22.9.2 : (Control Register) send Start condition (22.7.1) ! writting 1 to TWINT clears it (set it to 0)
@@ -28,6 +24,9 @@ void i2c_start(void) {
return i2c_stop();
}
}
void i2c_start_repeat(void) { // 22.7.1 : "Repeated START enables the Master to switch between Slaves, Master Transmitter mode and Master Receiver mode without losing control of the bus"
i2c_start();
}
void i2c_send_addr_w(uint8_t slave_address) {
if (i2c_status == STOP) {
@@ -93,8 +92,8 @@ uint8_t i2c_read_ack(void) {
TWCR = TWI_ACKNOWLEDGE; // 22.7.1 : Master Transmitter Mode
while (!(TEST(TWCR, TWINT))); // 22.7.1 : Wait for TWINT Flag set. This indicates that the SLA+R/W has been transmitted, and ACK/NACK has been received
uint8_t status = TWSR & 0b11111000; // p225 example code : Check status for Receiver mode. Mask prescaler bits. If status different from MT_DATA_ACK go to ERROR
if (status != TW_MT_DATA_ACK) {
uint8_t status = TWSR & 0b11111000; // Table 22-3 : check status for Receiver mode, mask prescaler bits
if (status != TW_MR_DATA_ACK) {
i2c_stop();
return 0;
}
@@ -110,8 +109,8 @@ uint8_t i2c_read_nack(void) {
TWCR = TWI_NACKNOWLEDGE; // 22.7.1 : Master Transmitter Mode
while (!(TEST(TWCR, TWINT))); // 22.7.1 : Wait for TWINT Flag set. This indicates that the SLA+R/W has been transmitted, and ACK/NACK has been received
uint8_t status = TWSR & 0b11111000; // p225 example code : Check status for Receiver mode. Mask prescaler bits. If status different from MT_DATA_ACK go to ERROR
if (status != TW_MT_DATA_NACK) {
uint8_t status = TWSR & 0b11111000; // Table 22-3 : check status for Receiver mode, mask prescaler bits
if (status != TW_MR_DATA_NACK) {
i2c_stop();
return 0;
}