AD8191 Analog Devices, AD8191 Datasheet - Page 19

• Manufacturer Part Number: AD8191
• Description: 4:1 DVI/HDMI Switch with Equalization Preliminary Data Sheet (Rev. PrJ, 8/2006)
• Manufacturer: Analog Devices

Preliminary Technical Data
READ PROCEDURE
To read data from the AD8191 register set, an I
as a microcontroller) needs to send the appropriate control
signals to the AD8191 slave device. The signals are controlled
by the I
the procedure, see Figure 16. The steps for a read procedure are
as follows:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. Wait for the AD8191 to acknowledge the request.
11. The AD8191 serially transfers the data (eight bits) held in
12. Acknowledge the data from the AD8191.
Send a start condition (while holding the I2C_SCL line
high, pull the I2C_SDA line low).
Send the AD8191 part address (seven bits). The upper four
bits of the AD8191 part address are the static value [1001]
and the 3-LSBs are set by the Input Pins I2C_ADDR2,
I2C_ADDR1 and I2C_ADDR0 (LSB). This transfer should
be MSB first.
Send the write indicator bit (0).
Wait for the AD8191 to acknowledge the request.
Send the register address (eight bits) from which data is to
be read. This transfer should be MSB first.
Wait for the AD8191 to acknowledge the request.
Send a repeated start condition (Sr) by holding the
I2C_SCL line high and pulling the I2C_SDA line low.
Resend the AD8191 part address (seven bits) from Step 2.
The upper four bits of the AD8191 part address are the
static value [1001] and the 3-LSBs are set by the Input Pins
I2C_ADDR2, I2C_ADDR1 and I2C_ADDR0 (LSB). This
transfer should be MSB first.
Send the read indicator bit (1).
the register indicated by the address set in Step 5. This data
is sent MSB first.
2
P
C master unless otherwise specified. For a diagram of
P
2
P
C master (such
P
Figure 15. I
Rev. PrJ | Page 19 of 29
2
C Read Diagram
13. Do one of the following:
a.
b.
c.
d.
Send a stop condition (while holding the I2C_SCL
line high, pull the SDA line high) and release control
of the bus to end the transaction (shown in Figure 15).
Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 of the write procedure (previous
Write Procedure section) to perform a write.
Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 of this procedure to perform a
read from another address.
Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 8 of this procedure to perform a
read from the same address.
AD8191