CDB5464U Datasheet, PDF (7/38 Pages) Cirrus Logic – CDB5464U Engineering Borad and GUI Software

CDB5464U
1.6 Auto-boot Mode
With a jumper connection on J18 (AUTO-BOOT ENABLE), the CS5464 operates in auto-boot mode and
the CDB5464U board operates as a stand-alone system without attaching it up to a PC. When in auto-
boot mode, a hardware reset (press on S1) will cause the CS5464 to boot up using the serial data from
the serial EEPROM on the board (U10). When the CS5464 is in auto-boot mode, the SPI connections
between the microcontroller and the CS5464 are removed and the GUI software can not access the
CS5464 registers and functions.
The EEPROM must be programmed prior to the auto-boot sequence. When the CDB5464U Evaluation
Board is sent from the factory, the EEPROM is programmed with the following CS5464 command/data
sequence:
1. Move to EEPROM page 1:
0x7E 0x00 0x00 0x01
2. Write Modes register, turn high-pass filters on:
0x60 0x00 0x01 0xE0
3. Move to EEPROM page 0:
0x7E 0x00 0x00 0x00
4. Set bit 2 (LSD) in the Mask register:
0x74 0x00 0x00 0x04
5. Start continuous conversion:
0xE8
6. Write STOP bit in Control register, to terminate auto-boot sequence:
0x78 0x00 0x01 0x00
This sequence programs the CS5464 for continuous conversion mode. If voltage and current signals are
applied to the inputs, the CS5464 will issue pulses on the E1 pin. See the CS5464 data sheet for more
details on auto-boot.
DS847DB1
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