SBASAV5 December 2023 ADS1114L , ADS1115L
PRODUCTION DATA
Figure 8-8 shows the format of the data transfer. The controller initiates all transactions with the ADS111xL by generating a START (S) condition. A high-to-low transition on the SDA line while SCL is high defines a START condition. The bus is considered to be busy after the START condition.
Following the START condition, the controller sends the 7-bit target address corresponding to the address of the ADS111xL that the controller wants to communicate with. The controller then sends an eighth bit that is a data-direction bit (R/W). An R/W bit of 0b indicates a write operation, and an R/W bit of 1b indicates a read operation. After the R/W bit, the controller generates a ninth SCLK pulse and releases the SDA line to allow the ADS111xL to acknowledge (ACK) the reception of the target address by pulling SDA low. If the device does not recognize the target address, the ADS111xL holds SDA high to indicate a not acknowledge (NACK) signal.
Data transmission follows next in the process. If the transaction is a read (R/W = 1b), the ADS111xL outputs data on SDA. If the transaction is a write (R/W = 0b), the host outputs data on SDA. Data are transferred byte-wise, most significant bit (MSB) first. The number of bytes that can be transmitted per transfer is unrestricted. Each byte must be acknowledged (with the ACK bit) by the receiver. If the transaction is a read, the controller issues the ACK bit. If the transaction is a write, the ADS111xL issues the ACK bit.
The controller terminates all transactions by generating a STOP (P) condition. A low-to-high transition on the SDA line while SCL is high defines a STOP condition. The bus is considered free again tBUF (bus-free time) after the STOP condition.