
CobraNet
TM
EV-2
Page 17
LED Control
There are two bit registers to control the state of each of three LEDs. The mapping of control bits
to LED behavior is described in Table 10 on page 17. The data bit is always AD0.
Calibrating the ADC
The CS5396 ADC requires approximately ten seconds to achieve proper operating temperature
after which, for optimal performance, it is necessary to initiate a calibration cycle. After power is
applied and after reset the EV-2 uses an internal timer to count off approximately 10 seconds
before beginning the calibration cycle. Prior to and during the calibration, the ADC calibration
status register will read 1. Once calibration has been completed, the status register will read 0.
Calibration can also be initiated manually by the microcontroller by writing a 1 to the Manual
ADC Calibration register and then immediately returning the register to the 0 state. The FPGA
initiates this one-time power up/reset calibration.
Version Control
The FPGA contains three hardwired eight-bit registers that contain an ASCII version/revision
number of the FPGA configuration file. The microcontroller can read these registers for version
control and reporting purposes.
Gain register
data bits
AD1 AD0
Gain
0
0
0dB
0
1
-6dB
1
0
-12dB
1
1
-18dB
Table 9: Sine Wave Gain Register Bit Definitions
Enable
Blink
Status
0
0
off
1
0
on
0
1
off
1
1
blink
Table 10: LED Status