DS1050/DS1052
The command operation
“Set Recall Mode”
is used to recall the DS1050/DS1052 from a low-current
state. The value of the PWM
O
output is recalled to that prior to initiating a “Set shutdown mode”
command.
The
“Read PWM Duty Cycle”
command is used to read the current setting of the PWM configuration
register. Information returned by this command includes PWM output value, as well as, whether the
device is in a shutdown configuration.
PWM data values and control/ command values are always transmitted most significant bit (MSB) first.
During communications, the receiving unit always generates the “acknowledge”.
Reading the DS1050/DS1052
As shown in Figure 4e, the DS1050/DS1052 provides one
read command operation.
This operation
allows the user to read the current setting of the PWM configuration register. Specifically, the R/W bit of
the command/control byte is set equal to a 1 for a read operation. Communication to read the
DS1050/DS1052 begins with a START condition which is issued by the master device. The
command/control byte from the master device will follow the START condition. Once the
command/control byte has been received by the DS1050/DS1052, the part will respond with an
ACKNOWLEDGE. The read/write bit of the command/control byte, as stated, should be set equal to '1'
for reading the DS1050/DS1052.
When the master has received the ACKNOWLEDGE from the DS1050/DS1052, the master can then
begin to receive the PWM configuration register data. As mentioned this data will be transmitted MSB
first. Once the eight bits of the PWM configuration register have been transmitted, the master will need
to issue an ACKNOWLEDGE, unless it is the only byte to be read, in which case the master issues a
NOT ACKNOWLEDGE. If desired the master may stop the communication transfer at this point by
issuing the STOP condition. Final communication transfer is terminated by issuing the STOP command.
Again, the flow of the read operation is presented in Figure 4e.
Writing the DS1050/DS1052
A data flow diagram for writing the DS1050/DS1052 is shown in Figure 4a,b,c, & d. The
DS1050/DS1052 has three write commands that are used to change the PWM configuration register or
the shutdown and recall mode of the device.
All the write operations begin with a START condition. Following the START condition, the master
device will issue the command/control byte. The read/write bit of the command/control byte will be set
to '0' for writing the DS1050/DS1052. Once the command/control byte has been issued and the master
receives the acknowledgment from the DS1050/DS1052, PWM configuration data is transmitted to the
DS1050/DS1052 by the master device.
A data byte for the DS1050/DS1052 will contain
PWM configuration data
and
shutdown/recall command
data.
The five least significant bits of data specify the PWM configuration value while the three most
significant bits specify the whether the device is to be shutdown or recalled. When the DS1050/DS1052
has received the data byte, it will respond with an ACKNOWLEDGE. At this point, the new PWM
configuration register
value and shutdown/recall command value will be updated in the
DS1050/DS1052. The master device, after the receipt of the ACKNOWLEDGE, can continue to transmit
additional data bytes or if the transaction is complete respond with the STOP condition. The 2-wire serial
timing diagram is presented in Figure 5.
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DALLAS [ DALLAS SEMICONDUCTOR ]
