CDB5461AU Cirrus Logic Inc, CDB5461AU Datasheet - Page 22

• Manufacturer Part Number: CDB5461AU
• Description: Eval Bd Sngl Phase Power/Energy
• Manufacturer: Cirrus Logic Inc

Specifications of CDB5461AU

• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: CS5461A
• Primary Attributes: 1-Phase, Energy-to-Frequency Output
• Secondary Attributes: GUI, USB, SPI, Microwire Interfaces
• Processor To Be Evaluated: CS5461A, C8051F320
• Interface Type: USB
• Operating Supply Voltage: 5 V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant, Contains lead / RoHS non-compliant
• Other names: 598-1552

5.13 Serial Port Overview
The CS5461A incorporates a serial port transmit and re-
ceive buffer with a command decoder that interprets
one-byte (8 bits) commands as they are received. There
are four types of commands; instructions, synchroniz-
ing, register writes and register reads (See
Commands
Instructions are one byte in length and will interrupt any
instruction currently executing. Instructions do not affect
register reads currently being transmitted.
Synchronizing commands are one byte in length and
only affect the serial interface. Synchronizing com-
mands do not affect operations currently in progress.
Register writes must be followed by three bytes of data.
register reads can return up to four bytes of data.
Commands and data are transferred most-significant bit
(MSB) first.
timing and required sequence necessary to write to and
read from the serial port receive and transmit buffer, re-
spectively. While reading data from the serial port, com-
mands and data can be simultaneously written. Starting
a new register read command while data is being read
will terminate the current read in progress. This is ac-
ceptable if the remainder of the current read data is not
needed. During data reads, the serial port requires input
22
Figure 1
on page 23).
on page 11, defines the serial port
Section 5.14
data. If a new command and data is not sent, SYNC0 or
SYNC1 must be sent.
5.13.1 Serial Port Interface
The serial port interface is a “4-wire” synchronous serial
communications interface. The interface is enabled to
start excepting SCLKs when CS (Chip Select) is assert-
ed. SCLK (Serial bit-clock) is a Schmitt-trigger input that
is used to strobe the data on SDI (Serial Data In) into the
receive buffer and out of the transmit buffer onto SDO
(Serial Data Out).
If the serial port interface becomes unsynchronized with
respect to the SCLK input, any attempt to clock valid
commands into the serial interface may result in unex-
pected operation. The serial port interface must then be
re-initialized by one of the following actions:
If a resynchronization is necessary, it is best to re-initial-
ize the part either by hardware or software reset (0x80),
as the state of the part may be unknown.
-
-
-
Drive the CS pin high, then low.
Hardware Reset (drive RESET pin low, for at
least 10 µs).
Issue the Serial Port Initialization Sequence,
which is 3 (or more) SYNC1 command bytes
(0xFF) followed by one SYNC0 command byte
(0xFE).
CS5461A
DS661F2