Cirrus Logic CDB5378 - Manual (Page 27)

CDB5378
DS639DB4 27
2.3.3 Digital Control Signals
The reset, synchronization and timebreak signals to the CS5378 digital filter can be generated by push
buttons, received from external inputs or generated by the on-board microcontroller. By default, push but-
tons SYNC_PB and TIMEB_PB and external inputs SYNC_EXT (J50) and TIMEB_EXT (J59) are con-
nected through the interface CPLD to the CS5378 digital filter SYNC and TIMEB inputs. In contrast, push
button RESET_PB is connected directly to the CS5378 digital filter reset through (J40 & J58) jumper con-
figurations.
A four-position DIP switch on CDB5378 (S5) sets static digital control signals not normally changed during
operation. The LGND signal (S5, #2) is connected to a logic ground pin of the CS3301A/02A device and
therefore needs to be held to ground. The PWDN signal (S5, #3) disables the analog components by plac-
ing them in a micropower sleep state.
2.3.4 Microcontroller
Included on CDB5378 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, I2C, 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
CDB5378 limit how the blocks can operate, so the port mapping of microcontroller resources is detailed
below.