LMH0318_15 Datasheet, PDF (16/57 Pages) Texas Instruments – LMH0318 3 Gbps HD/SD SDI Reclocker with Integrated Cable Driver

LMH0318
SNLS508 – SEPTEMBER 2015
www.ti.com
8.3.6 Fast EOM
Fast EOM is a mechanism that provides an option to read out EOM through SPI/SMBus interfaces by reading
the hits observed for each point of 64 × 64 points matrix. Since SPI interface operates at faster clock rate than
SMBus interface, the SPI master will have to wait until the EOM start bit, reg 0x24[0], goes low. This indicates
EOM samples are available and the SPI master can proceed to read register 0x25 and 0x26. See SPI Fast EOM
Operation and LMH0318 Programming Guide (SNLU183) for further details of Fast EOM operation.
8.3.6.1 SMBus Fast EOM Operation
In SMBus mode, the read on register 0x26 acts as an automatic trigger to read the next EOM count value:
1. Enable EOM (power it on), and set VRANGE=0. Write reg 0x24[7] to 1 to turn on fast EOM
2. Read register 0x25 as burst of 2 bytes (EOM hit count) and discard
3. Read register 0x25 as burst of 2 bytes (EOM hit count) and discard
4. Read register 0x25 as burst of 2 bytes (EOM hit count) and save
5. Perform Step 4 4095 times (64 × 64 cells)
8.3.6.2 SPI Fast EOM Operation
To perform EOM calculation over SPI:
1. Enable EOM (power it on), and set VRANGE=0. Write reg 0x24[7] to 1 to turn on fast EOM
2. Read reg 0x26 to initialize. Discard read data
3. Read Reg 0x24[0] which is EOM start bit. Wait for this bit to go low
4. Read register 0x26 EOM hit count and discard. Read on register 0x26 will automatically trigger the next Fast
Eye calculation
5. Read Reg 0x24[0]. Wait for this bit to go low
6. Do burst read on register 0x25 and 0x26 to get the EOM hit count value.
7. Repeat Steps 5 and 6 4095 times (64 × 64 cells)
8.3.7 LMH0318 Device Configuration
The control pins can be used to configure different operations depending on the functional modes as described
in Table 2.
PIN #
1
2
3
4
6
13
15
16
Table 2. Control Pins
PIN NAME
MODE_SEL
IN_OUT_SEL_SPI_SS_N_ADDR0
EQ_SCL_SCK
OUT_CTRL_MOSI_SDA
ENABLE
LOS_INT_N
VOD_MISO_ADDR1
LOCK
SPI
1 kΩ to VDD
SPI_SS_N
SPI_SCK
SPI_MOSI
ENABLE
LOS_INT_N
SPI_MISO
LOCK
FUNCTIONAL MODES
SMBus_Slave
1 kΩ to GND
ADDR0
SMBUS_SCL
SMBUS SDA
ENABLE
LOS_INT_N
ADDR1
LOCK
16
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