U2C-12 USB-I2C/SPI/GPIO Interface Adapter Users Manual

The “I2C Low Level” bar (Figure 2.14, “"I2C Low Level" Bar”) allows to work with the I²C slave devices on the low level.

Figure 2.14. "I2C Low Level" Bar

The “Start” button generates the START condition on the I²C bus, i.e. a HIGH to LOW transition of the SDA line while the SCL line is HIGH. The START condition (Figure 2.15, “The START condition”) indicates the beginning of the data exchange operation.

Figure 2.15. The START condition

The “ReStart” button generates the repeated START condition (Figure 2.16, “The repeated START condition”). It is used to allow combined write/read operations without releasing the bus and interrupting the operation.

Figure 2.16. The repeated START condition

The “Stop” button generates the STOP condition (Figure 2.17, “The STOP condition”) on the I²C bus, i.e. a HIGH to LOW transition of the SDA line while the SCL line is HIGH. The bus is considered to be free after the STOP condition.

Figure 2.17. The STOP condition

The “Write” button transmits the data byte from I²C master to I²C slave device. Enter the transmitted value into the “Write” field (integer hexadecimal value from 0 to FF).

If the "Ack" (Write) check-box is selected, acknowledge will be requested from the I²C slave device after the data byte transmission.

If the "Ack" (Write) check-box is not selected, acknowledge will not be requested. It may lead to the data loss. You can still press the "Get Ack" button to request acknowledge.

The “Read” button transmits the data byte from I²C slave to I²C master device. The information about the byte data requested is desplayed in the log field (Figure 2.18, “The information about the byte data reading with the "Ack" signal”).

Figure 2.18. The information about the byte data reading with the "Ack" signal

If the "Ack" (read) check-box is selected, acknowledge ("Ack" or "No Ack" depends on the value of “Put Ack” drop list) will be generated.

If "Ack" (read) check-box is not selected, acknowledge will not be generated. You can still press the “Put Ack” button to generate acknowledge. Without acknowledge the further data reading can be incorrect.

The “Get Ack” button requests acknowledge from the I²C slave device.

The “Put Ack” button generates acknowledge on the I²C bus ("Ack” or “No Ack” depends on the value of “Put Ack” drop list).