1.2 Device Selection

Devices Hardware Selection

Each secure element has a switch connection that enables the user to select a given device. Slide the DIP switch to the ON state to enable the device selection. Selecting the device connects the corresponding SDA line through the DIP switch. The SCL signals of all eight devices are connected together. A large value pull-up resistor on each SDA line of each device keeps the device in a low-current state when not selected. Note that the switch number shown on the top of the board (not the number on the switch) corresponds to the device identifier U# on the back of the board.

Figure 1-2. Device Selection
Table 1-1. Device Selection Switches
Switch # DIP Switch Device U# Secure Element Trust Element Type
SW1 1 U1 ATECC608C-TNGTLS Trust&GO
2, 3, 4 U2, U3, U4 ATECC608C-TFLXTLS TrustFLEX
SW2 5 U5 ECC608-TMNGTLS TrustMANAGER
6,7,8 U6, U7, U8 ATECC608C-MAHDA TrustCUSTOM
Attention: For revision #4 boards see 3 DT100104 Rev 4 Errata.

Devices Software Selection

After a specific device is selected, a specific I2C address must be used to address the given device type. While each device is initially programmed with a default I2C address, it is possible to overwrite this address. See the specific device data sheets for more information.
Table 1-2. Default I2C Addresses
Device Default 7-bit I2C Address 8-bit Programmed I2C Byte Value(1)
ATECC608C-TNGTLS 0x35 0x6A/0x6B
ATECC608C-TFLXTLS 0x36 0x6C/0x6D
ATECC608C-MAHDA 0x60 0xC0/0xC1
ECC608-TMNGTLS 0x38 0x70/0x71
Note:
  1. This is the I2C_Address byte value programmed into the ATECC608C device for Write/Read transactions.

Note that multiple devices can be enabled provided they have different I2C addresses. If multiple devices with the same address are selected, a failure occurs due to a conflict on the I2C bus.