STMicroelectronics /STM32U073 /I2C1 /I2C_ISR

Transmit data register empty (transmitters) This bit is set by hardware when the I2C_TXDR register is empty. It is cleared when the next data to be sent is written in the I2C_TXDR register. This bit can be written to 1 by software in order to flush the transmit data register I2C_TXDR. Note: This bit is set by hardware when PE = 0.

Transmit interrupt status (transmitters) This bit is set by hardware when the I2C_TXDR register is empty and the data to be transmitted must be written in the I2C_TXDR register. It is cleared when the next data to be sent is written in the I2C_TXDR register. This bit can be written to 1 by software only when NOSTRETCH = 1, to generate a TXIS event (interrupt if TXIE = 1 or DMA request if TXDMAEN = 1). Note: This bit is cleared by hardware when PE = 0.

Receive data register not empty (receivers) This bit is set by hardware when the received data is copied into the I2C_RXDR register, and is ready to be read. It is cleared when I2C_RXDR is read. Note: This bit is cleared by hardware when PE = 0.

Address matched (slave mode) This bit is set by hardware as soon as the received slave address matched with one of the enabled slave addresses. It is cleared by software by setting ADDRCF bit. Note: This bit is cleared by hardware when PE = 0.

Not Acknowledge received flag This flag is set by hardware when a NACK is received after a byte transmission. It is cleared by software by setting the NACKCF bit. Note: This bit is cleared by hardware when PE = 0.

Stop detection flag This flag is set by hardware when a STOP condition is detected on the bus and the peripheral is involved in this transfer: either as a master, provided that the STOP condition is generated by the peripheral. or as a slave, provided that the peripheral has been addressed previously during this transfer. It is cleared by software by setting the STOPCF bit. Note: This bit is cleared by hardware when PE = 0.

Transfer Complete (master mode) This flag is set by hardware when RELOAD = 0, AUTOEND = 0 and NBYTES data have been transferred. It is cleared by software when START bit or STOP bit is set. Note: This bit is cleared by hardware when PE = 0.

Transfer Complete Reload This flag is set by hardware when RELOAD = 1 and NBYTES data have been transferred. It is cleared by software when NBYTES is written to a non-zero value. Note: This bit is cleared by hardware when PE = 0. Note: This flag is only for master mode, or for slave mode when the SBC bit is set.

Bus error This flag is set by hardware when a misplaced Start or STOP condition is detected whereas the peripheral is involved in the transfer. The flag is not set during the address phase in slave mode. It is cleared by software by setting BERRCF bit. Note: This bit is cleared by hardware when PE = 0.

Arbitration lost This flag is set by hardware in case of arbitration loss. It is cleared by software by setting the ARLOCF bit. Note: This bit is cleared by hardware when PE = 0.

Overrun/Underrun (slave mode) This flag is set by hardware in slave mode with NOSTRETCH = 1, when an overrun/underrun error occurs. It is cleared by software by setting the OVRCF bit. Note: This bit is cleared by hardware when PE = 0.

Bus busy This flag indicates that a communication is in progress on the bus. It is set by hardware when a START condition is detected, and cleared by hardware when a STOP condition is detected, or when PE = 0.

Transfer direction (slave mode) This flag is updated when an address match event occurs (ADDR = 1).

0 (B_0x0): Write transfer, slave enters receiver mode.

1 (B_0x1): Read transfer, slave enters transmitter mode.

Address match code (slave mode) These bits are updated with the received address when an address match event occurs (ADDR = 1). In the case of a 10-bit address, ADDCODE provides the 10-bit header followed by the two MSBs of the address.