Resolving Address Collisions on Multi Sensor Circuit Boards
Resolve multi-sensor address collisions using pin-strapped dividers, digital multiplexers, or active translators sized against bus capacitance and firmware costs.
Pin Strapping
Hardware Setting
Hardware-based initialization techniques set the operating mode or address of an integrated circuit by connecting specific pins to fixed voltage levels. Pin strapping occurs during the power-up or reset phase when the device samples the logic state of its external terminals. Static logic allows a single silicon design to support multiple configurations without requiring non-volatile memory.
Circuit Implementation
Designers use pull-up or pull-down resistors to define the default state of these configuration inputs. Pin strapping often shares functional pins that transition to data or clock duties after the initialization window closes. Dual-use hardware conserves pin count on small packages.
The resistor values must be chosen to provide a clear logic level while not interfering with high-speed signals later.
System Flexibility
Manufacturers use this technique to enable or disable features such as internal regulators or specialized communication modes. Pin strapping allows a customer to select between different I2C addresses or SPI modes at the board level. Strapped terminals provide a reliable and tamper-proof way to lock in critical system settings.
Changes to the configuration require physical modifications to the PCB.
Verification Procedure
Proper timing is essential to ensure the device correctly captures the intended state. Pin strapping requires the voltage levels to be stable before the reset line is released.