Datasheet LTC4318 (Analog Devices) - 9
| Fabricante | Analog Devices |
| Descripción | Dual I2C/SMBus Address Translator |
| Páginas / Página | 16 / 9 — operaTion System Configurations. Setting the Translation Byte. Figure 4. … |
| Formato / tamaño de archivo | PDF / 225 Kb |
| Idioma del documento | Inglés |
operaTion System Configurations. Setting the Translation Byte. Figure 4. Two Slaves Sharing One Channel of LTC4318
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LTC4318
operaTion System Configurations
7-bit translation byte. These voltages are referenced to There are several ways that individual slaves or banks of VCC so a resistive divider at each of these pins is the most slaves can be connected to an LTC4318. In Figure 3, each convenient way to set the voltages. The required transla- slave is paired with one channel of the LTC4318. This tion byte can be determined by taking the bitwise XOR of configuration allows for maximum flexibility in allocating the slave’s original address and the desired input address. the bus addresses. Both read and write operations and all The voltages at the XORH and XORL pins configure the protocols supported by the LTC4318 are allowed. Figure 4 translation byte. The XORL voltage configures the lower 4 shows two slaves with different hardwired addresses translation bits (excluding the R/W bit), while the XORH translated to two different addresses using one channel of voltage configures the upper 3 translation bits. Tables 2 the LTC4318 and a common translation byte. A program and 3 show the recommended resistive divider values. RLT is available to help the user visualize an I2C bus with the and RLB are the top and bottom resistors connected to LTC4318; this program can be found in the following link: XORL, while RHT and RHB are the top and bottom resistors www.linear.com/TranslatorTool connected to XORH (Figure 5). Use 1% tolerance resistors for RLT, RLB, RHT and RHB.
Setting the Translation Byte
When the LTC4318 is first powered up or any time a rising edge is detected on the ENABLE pin, the LTC4318 reads SCL the voltages at the XORH and XORL pins to determine the SLAVE #2 SDA HARDWIRED ADDRESS SLAVE #1 0x34 INPUT ADDRESS SCL 0x32 SCLIN SCLOUT SCL TRANSLATION BYTE MASTER 00110110 0x06 SLAVE SDA LTC4318 00000010 #1 00110100 SCLIN1 SCLOUT1 SCL SDAIN SDAOUT SDA SLAVE 00110010 LTC4318 HARDWIRED ADDRESS #1 00000110 TRANSLATION BYTE 0x34 00110100 0x02 SDAIN1 SDAOUT1 SDA SLAVE #1 SCL HARDWIRED ADDRESS INPUT ADDRESS 00110010 0x34 0x36 SLAVE 00000010 #3 SLAVE #3 00110000 SCLIN2 SCLOUT2 SCL INPUT ADDRESS SDA 00110110 0x32 SLAVE 00000010 HARDWIRED ADDRESS #3 00110100 0x30 4318 F04 SDAIN2 SDAOUT2 SDA SLAVE #3 HARDWIRED ADDRESS
Figure 4. Two Slaves Sharing One Channel of LTC4318
INPUT ADDRESS 0x34 SCL 0x36 TRANSLATION BYTE MASTER 0x02 VCC SDA SCL VCC RHT RLT SLAVE LTC4318 #2 XORH XORL SDA HARDWIRED ADDRESS RHB RLB 0x34 4318 F03 4318 F05
Figure 3. Two Independent Address Translation Figure 5. Address Translation Byte Configuration Resistors
4318fa For more information www.linear.com/LTC4318 9
operaTion System Configurations
7-bit translation byte. These voltages are referenced to There are several ways that individual slaves or banks of VCC so a resistive divider at each of these pins is the most slaves can be connected to an LTC4318. In Figure 3, each convenient way to set the voltages. The required transla- slave is paired with one channel of the LTC4318. This tion byte can be determined by taking the bitwise XOR of configuration allows for maximum flexibility in allocating the slave’s original address and the desired input address. the bus addresses. Both read and write operations and all The voltages at the XORH and XORL pins configure the protocols supported by the LTC4318 are allowed. Figure 4 translation byte. The XORL voltage configures the lower 4 shows two slaves with different hardwired addresses translation bits (excluding the R/W bit), while the XORH translated to two different addresses using one channel of voltage configures the upper 3 translation bits. Tables 2 the LTC4318 and a common translation byte. A program and 3 show the recommended resistive divider values. RLT is available to help the user visualize an I2C bus with the and RLB are the top and bottom resistors connected to LTC4318; this program can be found in the following link: XORL, while RHT and RHB are the top and bottom resistors www.linear.com/TranslatorTool connected to XORH (Figure 5). Use 1% tolerance resistors for RLT, RLB, RHT and RHB.
Setting the Translation Byte
When the LTC4318 is first powered up or any time a rising edge is detected on the ENABLE pin, the LTC4318 reads SCL the voltages at the XORH and XORL pins to determine the SLAVE #2 SDA HARDWIRED ADDRESS SLAVE #1 0x34 INPUT ADDRESS SCL 0x32 SCLIN SCLOUT SCL TRANSLATION BYTE MASTER 00110110 0x06 SLAVE SDA LTC4318 00000010 #1 00110100 SCLIN1 SCLOUT1 SCL SDAIN SDAOUT SDA SLAVE 00110010 LTC4318 HARDWIRED ADDRESS #1 00000110 TRANSLATION BYTE 0x34 00110100 0x02 SDAIN1 SDAOUT1 SDA SLAVE #1 SCL HARDWIRED ADDRESS INPUT ADDRESS 00110010 0x34 0x36 SLAVE 00000010 #3 SLAVE #3 00110000 SCLIN2 SCLOUT2 SCL INPUT ADDRESS SDA 00110110 0x32 SLAVE 00000010 HARDWIRED ADDRESS #3 00110100 0x30 4318 F04 SDAIN2 SDAOUT2 SDA SLAVE #3 HARDWIRED ADDRESS
Figure 4. Two Slaves Sharing One Channel of LTC4318
INPUT ADDRESS 0x34 SCL 0x36 TRANSLATION BYTE MASTER 0x02 VCC SDA SCL VCC RHT RLT SLAVE LTC4318 #2 XORH XORL SDA HARDWIRED ADDRESS RHB RLB 0x34 4318 F03 4318 F05
Figure 3. Two Independent Address Translation Figure 5. Address Translation Byte Configuration Resistors
4318fa For more information www.linear.com/LTC4318 9