Cirrus Logic CDB5376 - Manual (Page 27)

CDB5376
DS612DB3 27
2.3.3 Digital Control Signals
The reset, synchronization, and timebreak signals to the CS5376A digital filter can be generated by push
buttons, received from external inputs or generated by the on-board microcontroller. By default, the push
button RESET_PB, SYNC_PB, and TIMEB_PB signals are connected through the interface CPLD to the
CS5376A digital filter RESET, SYNC, and TIMEB inputs.
A four-position DIP switch on CDB5376 (S5) sets static digital control signals not normally changed during
operation. The BOOT signal (S5, #1) controls how the CS5376A digital filter receives configuration data,
either from a microcontroller or serial EEPROM. The LGND signal (S5, #3) is connected to logic ground
pins of the CS3301A/02A and CS5372A devices and therefore needs to be held to ground. The OFST
signal (S5, #4) enables the internal offset within the CS5372A modulator device to eliminate
∆Σ idle tones
from a terminated input.
2.3.4 Microcontroller
Included on CDB5376 is an 8051-type microcontroller with integrated hardware SPI and USB interfaces.
This C8051F320 microcontroller is a product of Silicon Laboratories (
http://www.silabs.com ). Key features
of the C8051F320 microcontroller are:
8051 compatibility - uses industry-standard 8051 software development tools
In-circuit debugger - software development on the target hardware
Internal memory - 16k flash ROM and 2k static RAM included on-chip
Multiple serial connections - SPI, USB, I
2
C, and UART
High performance - 25 MIPS maximum
Low power - 0.6 mA @ 1 MHz w/o USB, 9 mA @ 12 MHz with USB
Small size - 32 pin LQFP package, 9mm x 9mm
Industrial temperature - full performance (including USB) from -40 C to +85 C
Internal temperature sensor - with range violation interrupt capability
Internal timers - four general purpose plus one extended capability
Power on reset - can supply a reset signal to external devices
Analog ADC - 10 bit, 200 ksps SAR with internal voltage reference
Analog comparators - arbitrary high/low voltage compare with interrupt capability
The exact use of these features is controlled by embedded firmware.
C8051F320 has dedicated pins for power and the USB connection, plus 25 general-purpose I/O pins that
connect to the various internal resources through a programmable crossbar. Hardware connections on
CDB5376 limit how the blocks can operate, so the port mapping of microcontroller resources is detailed
below.