Freescale Semiconductor MPC5553 - Page 844

MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor 19-89
19.4.5.5 ADC Control Logic Overview and Command Execution
Figure 19-51 shows the basic logic blocks involved in the ADC control and how they interact.
CFIFOs/RFIFOs interact with ADC command/result message return logic through the FIFO control unit.
The EB and BN bits in the command message uniquely identify the ADC to which a command should be
sent. The FIFO control unit decodes these bits and sends the ADC command to the proper ADC. Other
blocks of logic are the result format and calibration submodule, the time stamp logic, and the MUX control
logic.
0 1 23456789101112131415
0 GCC_INT GCC_FRAC
Figure 19-50. Gain Calibration Constant Format
Table 19-48. Gain Calibration Constant Format Field Descriptions
Bits Name Description
0—Reserved
1 GCC_INT
[0]
Integer part of the gain calibration constant for ADCn. GCC_INT is the integer part of
the gain calibration constant (GCC) for ADC0/1.
2–15 GCC_FRAC
[1:14]
Fractional part of the gain calibration constant for ADCn. GCC_FRAC is the fractional
part of the gain calibration constant (GCC) for ADCn. GCC_FRAC can expresses
decimal values ranging from 0 to 0.999938...
Table 19-49. Correspondence between Binary and Decimal
Representations of the Gain Constant
Gain Constant
(GCC_INT.GCC_FRAC binary format)
Corresponding Decimal Value
0.0000_0000_0000_00 0
... ...
0.1000_0000_0000_00 0.5
... ...
0.1111_1111_1111_11 0.999938...
1.0000_0000_0000_00 1
... ...
1.1100_0000_0000_00 1.75
... ...
1.1111_1111_1111_11 1.999938...
Gain Calibration Constant (GCC)