Texas Instruments LMH0318, Руководство программиста

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Access Methods
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1 Access Methods
Two methods are provided for accessing the LMH0318 Registers:
• Register control via the Serial Management Bus (SMBus)
• Register control via the Serial Parallel Interface (SPI)
In a typical system, either SMBus or SPI access is used to configure and monitor the device status.
Unless specified, the register configurations for SPI and SMBus are the same.
1.1 Register Programming via SMBus and SPI Interface
The LMH0318 internal registers can be accessed through standard SMBus or SPI protocol. The SMBUS
Mode is enabled by setting MODE_SEL pin = LOW (1 k
Ω to GND). Pins associated with SMBus interface
are:
* ADDR0 (pin #2): Strap pin used to set the SMBus address
* ADDR1 (pin #15): Strap pin used to set the SMBus address
* SDA (pin #14): SMBus data pin
* SCL (pin #3): SMBus clock pin
The SMBus slave address is strapped at power up based on the configuration of the ADDR0 and ADDR1
pins. The state of these two pins are read on power up - after the internal power-on reset signal is de-
asserted. The maximum operating speed supported on the SMBus is 400 kHz.
There are 16 unique SMBus addresses that can be assigned to each device by placing external Resistor
straps on the ADDR0 and ADDR1 pins (pin #2 and #15).
1.1.1 SMBus Slave Address
ADDR0 ADDR1
ADDR0 ADDR1 7-bit SMBus Address
(1)
8-bit SMBus Write Address
Binary Binary
1 k Ω to GND 1 k Ω to GND 00 00 0D 1A
1 k Ω to GND 20 k Ω to GND 00 01 0E 1C
1 k Ω to GND Float 00 10 0F 1E
1 k Ω to GND 1 k Ω to VDD 00 11 10 20
20 k Ω to GND 1 k Ω to GND 01 00 11 22
20 k Ω to GND 20 k Ω to GND 01 01 12 24
20 k Ω to GND Float 01 10 13 26
20 k Ω to GND 1 k Ω to VDD 01 11 14 28
Float 1 k Ω to GND 10 00 15 2A
Float 20 k Ω to GND 10 01 16 2C
Float Float 10 10 17 2E
(2)
Float 1 k Ω to VDD 10 11 18 30
1 k Ω to VDD 1 k Ω to GND 11 00 19 32
1 k Ω to VDD 20 k Ω to GND 11 01 1A 34
1 k Ω to VDD Float 11 10 1B 36
1 k Ω to VDD 1 k Ω to VDD 11 11 1C 38
(1)
Seven (7) bit SMBus addresses need to include LSB equal to zero for write and 1 for read operation. For example, for 7 bit hex
address 0x0D, the controlling program should use I2C hex address 0x1A to write and 0X1B to read. This is true for other
addresses as well.
(2)
Default SMBus Address
2 LMH0318 Programming Guide SNLU183 – September 2015
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