Datasheet

7.3 I
2
C Address Selection
EVM Feature Details www.ti.com
Three input pins on the TPS2459 are assigned for setting the device I
2
C address: A2, A1 and A0. These
pins are tri-level inputs, allowing the device to be assigned any one of 27 unique address values. These
pins can be tied to ground potential to generate a logic low (L), pulled up to the VINT pin to generate a
logic high (H), or left open to float to a mid-range, no-connect (NC) level. On the EVM, address selection
is performed using switch S4. However, S4 is a common 4-position, 2-throw DIP switch. The switch is
wired into the circuit to pull the corresponding input pin to ground (L) when its DIP position is closed.
When a DIP position is open (O), the corresponding pin floats. Therefore, the address space for the EVM
is limited to an 8-value subset of the addresses recognized by the TPS2459. Table 8 specifies the valid
address space of the TPS2459EVM. Note that switch position S4-4 is not connected to any of the device
pins.
Table 8. TPS2459EVM Valid I
2
C Addresses
S3 Position Device Address
A2 A1 A0 Ternary Decimal
L L L 0003 + 223 0 + 8 = 8
L L O 0013 + 223 1 + 8 = 9
L O L 0103 + 223 3 + 8 = 11
L O O 0113 + 223 4 + 8 = 12
O L L 1003 + 223 9 + 8 = 17
O L O 1013 + 223 10 + 8 = 18
O O L 1103 + 223 12 + 8 = 20
O O O 1113 + 223 13 + 8 = 21
16 TPS2459 Full-Featured AdvancedMC™ Slot Controller Evaluation Module SLUU349 – March 2009
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