An electronic module (100, 300) comprising: a power supply terminal (110, 310) configured to receive power; data detection circuitry (344, 346, 354) coupled to detect signal levels at the power supply terminal; and control circuitry coupled to the data detection circuitry, the control circuitry being configured to: receive a first mode selection signal via the power supply terminal based on the signal levels detected by the data detection circuitry; in response to receiving the first mode selection signal, begin receiving input data via the power supply terminal based on the signal levels detected by the data detection circuitry; and perform an operation using the input data; characterised in that the data detection circuitry includes a voltage divider network coupled to the power supply terminal at a first end and to ground at a second end; a first comparator configured to detect the first mode selection signal by comparing a first voltage-divided signal received via the voltage divider network with a first predetermined signal level; and a second comparator configured to detect the input data on the power supply terminal by comparing a second voltage-divided signal received via the voltage divider network with a second predetermined signal level. a power supply terminal (110, 310) configured to receive power; data detection circuitry (344, 346, 354) coupled to detect signal levels at the power supply terminal; and control circuitry coupled to the data detection circuitry, the control circuitry being configured to: receive a first mode selection signal via the power supply terminal based on the signal levels detected by the data detection circuitry; in response to receiving the first mode selection signal, begin receiving input data via the power supply terminal based on the signal levels detected by the data detection circuitry; and perform an operation using the input data; characterised in that the data detection circuitry includes a voltage divider network coupled to the power supply terminal at a first end and to ground at a second end; a first comparator configured to detect the first mode selection signal by comparing a first voltage-divided signal received via the voltage divider network with a first predetermined signal level; and a second comparator configured to detect the input data on the power supply terminal by comparing a second voltage-divided signal received via the voltage divider network with a second predetermined signal level. receive a first mode selection signal via the power supply terminal based on the signal levels detected by the data detection circuitry; in response to receiving the first mode selection signal, begin receiving input data via the power supply terminal based on the signal levels detected by the data detection circuitry; and perform an operation using the input data; characterised in that the data detection circuitry includes a voltage divider network coupled to the power supply terminal at a first end and to ground at a second end; a first comparator configured to detect the first mode selection signal by comparing a first voltage-divided signal received via the voltage divider network with a first predetermined signal level; and a second comparator configured to detect the input data on the power supply terminal by comparing a second voltage-divided signal received via the voltage divider network with a second predetermined signal level.