Datasheet LTC4316 (Analog Devices) - 7
| Manufacturer | Analog Devices |
| Description | Single I2C/SMBus Address Translator |
| Pages / Page | 16 / 7 — OPERATION. Figure 1. Basic Functions of the LTC4316. Figure 2. Basic … |
| File Format / Size | PDF / 212 Kb |
| Document Language | English |
OPERATION. Figure 1. Basic Functions of the LTC4316. Figure 2. Basic Address Translation Waveforms
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LTC4316
OPERATION
Figure 1 shows an I2C master connected to the input bus SDAOUT pin. Once all 7 bits of the address are processed, of the LTC4316 (SCLIN and SDAIN). The slave devices the LTC4316 turns on N2 again to reconnect SDAIN to requiring address translation are connected to the output SDAOUT. The master then transmits the R/W bit directly bus of the LTC4316 (SCLOUT and SDAOUT). Any other to the slave. If the new, translated address on SDAOUT slave devices that do not require address translation are matches the slave’s address, the slave pulls SDAOUT low placed together with the master on the input bus of the to acknowledge (ACK bit). N2 remains on and the rest of LTC4316. Two switches (N1 and N2) inside the LTC4316 the data bytes are transmitted unmodified between the connect the input bus to the output bus. N1 connects master and slave. The address translation process restarts SCLIN to SCLOUT while N2 connects SDAIN to SDAOUT. when the master issues a new START bit. In most conditions, N1 and N2 stay on so that the input Figure 2 shows typical waveforms for the circuit on the and output buses are connected. front page. In this example, the master transmits address Translation starts when the master issues a START bit 0x34 while the slave is configured to respond to address (SDAIN goes low while SCLIN is high). The LTC4316 0x36. The resistive dividers at the XORL and XORH pins are turns off N2 to disconnect SDAIN from SDAOUT. As the configured to generate an address translation byte of 0x02. master sends the address byte, the LTC4316 translates Note that in this example, the 8-bit hexadecimal address the incoming address at the SDAIN pin to a new address format (with R/W=0) is used. 7-bit addresses are also at the SDAOUT pin by XORing each incoming bit with commonly found in I2C device documentation. Make sure a user-configurable translation byte, one bit at a time. to use the correct format when calculating the address N3 turns on and off to send out the new address to the translation byte. Table 1 shows examples of both formats. VCC1 VCC2 LTC4316 SCLIN N1 SCLOUT MASTER SLAVE #1 SDAIN N2 SDAOUT CMP2 + N3 SLAVE XOR #2 1.8V – 0 0 0 0 0 1 0 ENABLE 7-BIT ADDRESS TRANSLATION ADDRESS BYTE SHIFT REGISTER TRANSLATION 4316 F01
Figure 1. Basic Functions of the LTC4316
R/W ACK START ADDRESS BITS BIT BIT a6 a5 a4 a3 a2 a1 a0 SCLIN SDAIN 0 0 1 1 0 1 0 0 = 0x34 TRANSLATION BYTE 0 0 0 0 0 0 1 0 = 0x02 SDAOUT 0 0 1 1 0 1 1 0 = 0x36 N2 GATE N2 ON N2 OFF N2 ON 4316 F02
Figure 2. Basic Address Translation Waveforms
4316fa For more information www.linear.com/LTC4316 7
OPERATION
Figure 1 shows an I2C master connected to the input bus SDAOUT pin. Once all 7 bits of the address are processed, of the LTC4316 (SCLIN and SDAIN). The slave devices the LTC4316 turns on N2 again to reconnect SDAIN to requiring address translation are connected to the output SDAOUT. The master then transmits the R/W bit directly bus of the LTC4316 (SCLOUT and SDAOUT). Any other to the slave. If the new, translated address on SDAOUT slave devices that do not require address translation are matches the slave’s address, the slave pulls SDAOUT low placed together with the master on the input bus of the to acknowledge (ACK bit). N2 remains on and the rest of LTC4316. Two switches (N1 and N2) inside the LTC4316 the data bytes are transmitted unmodified between the connect the input bus to the output bus. N1 connects master and slave. The address translation process restarts SCLIN to SCLOUT while N2 connects SDAIN to SDAOUT. when the master issues a new START bit. In most conditions, N1 and N2 stay on so that the input Figure 2 shows typical waveforms for the circuit on the and output buses are connected. front page. In this example, the master transmits address Translation starts when the master issues a START bit 0x34 while the slave is configured to respond to address (SDAIN goes low while SCLIN is high). The LTC4316 0x36. The resistive dividers at the XORL and XORH pins are turns off N2 to disconnect SDAIN from SDAOUT. As the configured to generate an address translation byte of 0x02. master sends the address byte, the LTC4316 translates Note that in this example, the 8-bit hexadecimal address the incoming address at the SDAIN pin to a new address format (with R/W=0) is used. 7-bit addresses are also at the SDAOUT pin by XORing each incoming bit with commonly found in I2C device documentation. Make sure a user-configurable translation byte, one bit at a time. to use the correct format when calculating the address N3 turns on and off to send out the new address to the translation byte. Table 1 shows examples of both formats. VCC1 VCC2 LTC4316 SCLIN N1 SCLOUT MASTER SLAVE #1 SDAIN N2 SDAOUT CMP2 + N3 SLAVE XOR #2 1.8V – 0 0 0 0 0 1 0 ENABLE 7-BIT ADDRESS TRANSLATION ADDRESS BYTE SHIFT REGISTER TRANSLATION 4316 F01
Figure 1. Basic Functions of the LTC4316
R/W ACK START ADDRESS BITS BIT BIT a6 a5 a4 a3 a2 a1 a0 SCLIN SDAIN 0 0 1 1 0 1 0 0 = 0x34 TRANSLATION BYTE 0 0 0 0 0 0 1 0 = 0x02 SDAOUT 0 0 1 1 0 1 1 0 = 0x36 N2 GATE N2 ON N2 OFF N2 ON 4316 F02
Figure 2. Basic Address Translation Waveforms
4316fa For more information www.linear.com/LTC4316 7
