Cirrus Logic CDB5528 - Manual (Page 19)

CDB5521/22/23/24/28
DS317DB2 19
2.9 Calibration Window Overview
The following controls and indicators are associat-
ed with the Calibration Menu (Figure 9).
• GAIN DECODE
Eight display boxes that displays the decoded
meaning of each gain register.
• Gain Hexadecimal Icons
Eight input/display icons that allow a user to
set/clear the 24 bits in the eight gain registers
via 6 hexadecimal nibbles. If the upper nibbles
in the registers are zero’s, then leading zero
nibbles need to be entered.
• Offset Hexadecimal Icons
Eight input/display icons that allow a user to
set/clear the 24 bits in the eight offset registers
via 6 hexadecimal nibbles. If the upper nibbles
in the registers are zero’s, then leading zero
nibbles need to be entered.
• Self-Gain
Used to perform a self-gain calibration using
the chosen Setup.
• Self-Offset
Used to perform a self-offset calibration using
the chosen Setup.
• Shift Gain Register
Sixteen input icons used to shift the contents on
the gain registers either 1 bit left or right. Once
shifted the data at the respective gain registers
ends is lost.
• System-Gain
Used to perform a system-gain calibration us-
ing the chosen Setup.
• System-Offset
Used to perform a system-offset calibration us-
ing the chosen Setup.
• Update Icons
This is a control icon. When pressed the offset
and gain registers are read. Then, the register
content icons are updated.
2.10 Trouble Shooting the Evaluation Board
This section describes special test modes incorporated
in the microcontroller software to diagnose hardware
problems with the evaluation board.
Note: To enter these modes, set the test switches to the
appropriate position and reset the evaluation
board. To re-enter the normal operation mode, set
the switches back to binary zero and reset the
board again.
• Test Mode 0, Normal Mode
This is the default mode of operation. To enter
this mode, set the test switches to 000 and reset
the board. The evaluation board allows normal
read/writes to the ADC’s registers. All the
LED’s toggle on then off after reset, and then
only when communicating with the PC.
• Test Mode 1, Loop Back Test
This test mode checks the microcontroller’s on-
chip UART. To enter this mode, set test switch-
es to 001, set HDR7 for loop back, and then re-
set the board. If the communication works, all
the LED's toggle. Otherwise, only 1/2 of the
LED’s toggle to indicate a communication
problem.
• Test Mode 2, Read/Write to ADC
This test mode tests the microcontroller’s abil-
ity to read and write to the ADC. To enter this
mode, set the switches to 010 and reset the
board. In this test mode, the ADC’s configura-
tion, offset, and gain registers are written to and
then read from. If the correct data is read back,
all the LED's toggle. Otherwise, only half of
them toggle to indicate an error.