AD8190
Rev. 0 | Page 15 of 24
START
FIXED PART ADDR
REGISTER ADDR
FIXED PART ADDR
DATA
STOP
ACK
ADDR ACK
R/W
ADDR ACK
ACK
R/W
SR
1
2
3
4
5
6
7
8
9 10 11
12
13
I2C_SCL
GENERAL CASE
I2C_SDA
EXAMPLE
I2C_SDA
06
12
2-
0
09
Figure 30. I2C Read Procedure
READ PROCEDURE
To read data from the AD8190 register set, an I2C master (such
as a microcontroller) needs to send the appropriate control
signals to the AD8190 slave device. The signals are controlled
by the I2C master unless otherwise specified. For a diagram of
as follows:
1.
Send a start condition (while holding the I2C_SCL line
high, pull the I2C_SDA line low).
2.
Send the AD8190 part address (seven bits). The upper six
bits of the AD8190 part address are the static value
[100100] and the LSB is set by Input Pin I2C_ADDR. This
transfer should be MSB first.
3.
Send the write indicator bit (0).
4.
Wait for the AD8190 to acknowledge the request.
5.
Send the register address (eight bits) from which data is to
be read. This transfer should be MSB first.
6.
Wait for the AD8190 to acknowledge the request.
7.
Send a repeated start condition (Sr) by holding the
I2C_SCL line high and pulling the I2C_SDA line low.
8.
Resend the AD8190 part address (seven bits) from Step 2.
The upper six bits of the AD8190 part address compose the
static value [100100]. The LSB is set by Input Pin I2C_ADDR.
This transfer should be MSB first.
9.
Send the read indicator bit (1).
10. Wait for the AD8190 to acknowledge the request.
11. The AD8190 serially transfers the data (eight bits) held in
the register indicated by the address set in Step 5. This data
is sent MSB first.
12. Acknowledge the data from the AD8190.
13. Do one of the following:
a.
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 30).
b.
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 (see the
c.
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.
d.
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.
SWITCHING/UPDATE DELAY
There is a delay between when a user writes to the configura-
tion registers of the AD8190 and when that state change takes
physical effect. This update delay begins at the falling edge of
I2C_SCL for the last data bit transferred, as shown in
Figure 29.This update delay is register specific and the times are specified
During a delay window, new values can be written to the
configuration registers but the AD8190 does not physically
update until the end of that register’s delay window. Writing
new values during the delay window does not reset the window;
new values supersede the previously written values. At the end
of the delay window, the AD8190 physically assumes the state
indicated by the last set of values written to the configuration
registers. If the configuration registers are written after the delay
window ends, the AD8190 immediately updates and a new
delay window begins.