CS5464 View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
CS5464 Datasheet PDF : 46 Pages
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CS5464
8. AUTO-BOOT MODE USING E2PROM
When the CS5464 MODE pin is asserted (logic 1), the
CS5464 auto-boot mode is enabled. In auto-boot mode,
the CS5464 downloads the required commands and
register data from an external serial E2PROM, allowing
the CS5464 to begin performing energy measurements.
8.1 Auto-boot Configuration
A typical auto-boot serial connection between the
CS5464 and a E2PROM is illustrated in Figure 18. In au-
to-boot mode, the CS5464’s CS and SCLK are config-
ured as outputs. The CS5464 asserts CS (logic 0),
provides a clock on SCLK, and sends a read command
to the E2PROM on SDO. The CS5464 reads the us-
er-specified commands and register data presented on
the SDI pin. The E2PROM’s programmed data is utilized
by the CS5464 to change the designated registers’ de-
fault values and begin registering energy.
VD+
5K
E1
E2
CS5464
SCLK
SDI
SDO
MODE
CS
Pulse Output
Counter
5K
EEPROM
SCK
SO
SI
CS
Connector to Calibrator
Figure 18. Typical Interface of E2PROM to CS5464
Figure 18 also shows the external connections that
would be made to a calibrator device, such as a PC or
custom calibration board. When the metering system is
installed, the calibrator would be used to control calibra-
tion and/or to program user-specified commands and
calibration values into the E2PROM. The user-specified
commands/data will determine the CS5464’s exact op-
eration, when the auto-boot initialization sequence is
running. Any of the valid commands can be used.
8.2 Auto-boot Data for E2PROM
Below is an example code set for an auto-boot se-
quence. This code is written into the E2PROM by the us-
er. The serial data for such a sequence is shown below
in single-byte hexidecimal notation:
-7E 00 00 01
Change to page 1.
-60 00 01 E0
Write Operation Mode Register, turn high-pass
filters on.
-42 7F C4 A9
Write value of 0x7FC4A9 to Current Gain
Register.
-46 FF B2 53
Write value of 0xFFB253 to Voltage Gain
Register.
-50 7F C4 A9
Write value of 0x7FC4A9 to Current 2 Gain
Register.
-54 FF B2 53
Write value of 0xFFB253 to Voltage 2 Gain
Register.
-7E 00 00 00
Change to page 0.
-74 00 00 04
Unmask bit #2 (LSD) in the Mask Register.
-E8
Start continuous conversions
-78 00 01 00
Write STOP bit to Control Register, to terminate
auto-boot initialization sequence.
8.3 Which E2PROMs Can Be Used?
Several industry-standard serial E2PROMs that will suc-
cessfully run auto-boot with the CS5461A are listed be-
low:
• Atmel AT25010, AT25020 or AT25040
• National Semiconductor NM25C040M8 or NM25020M8
• Xicor X25040SI
These types of serial E2PROMs expect a specific 8-bit
command (00000011) in order to perform a memory
read. The CS5461A has been hardware programmed to
transmit this 8-bit command to the E2PROM at the be-
ginning of the auto-boot sequence.
42
DS682PP1
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