7.1.1 I2C Hardware Interface

A summary of the hardware interface pins is shown below:

Table 7-1. Interface Pins
PinFunction
SCLSerial Clock to Host I2C
SDASerial Data to Host I2C
TSTransfer Status Line
Note: Inter-IC control signals (MODE, SYNC and TX) are described in the mXT2912TG / mXT2113TG data sheet.

The MXG3141 requires a dedicated Transfer Status line (TS). The MXG3141 (I2C Client) uses this line to inform the host controller (I2C Host) that there is data available which can be transferred. The TS line is electrically open-drain and requires a pull-up resistor of typically 10 kΩ from the TS line to VDD. The TS Idle state is high.

The MXG3141 uses an internal I2C message buffer. If after a read operation there are remaining messages in the buffer, the TS will only go high for a short-time period and then be driven low again.

Table 7-2. Usage of TS Line
DeviceTS LineStatus
Released (H)HighNo new pending message from the device
Asserted (L)LowNew message from device available; Host can start reading I2C message
Figure 7-1. Example for TS Line Indication and Following Read Operation
Note: The TS line handling of the MXG3141 is different to MGC3x30 devices. With the MXG3141, there is no need for the host to assert the TS line.
Important: Usage of TS line is compulsory. Trying to read the MXG3141 internal message buffer without waiting for TS signal, as specified above, could lead to corrupted data and abnormal interface behavior. Consequently, an appropriate dedicated input port must be planned on the host processor. The TS line must be dedicated to MXG3141 and cannot be shared with the maXTouch /CHG line.