MC3S12RG128 Datasheet, PDF (230/546 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 8 Analog-to-Digital Converter (ATD10B8CV3)
8.3.2.7 ATD Status Register 0 (ATDSTAT0)
This read-only register contains the sequence complete flag, overrun flags for external trigger and FIFO
mode, and the conversion counter.
Module Base + 0x0006
7
R
SCF
W
6
5
4
3
0
0
ETORF
FIFOR
Reset
0
0
0
0
0
= Unimplemented or Reserved
2
CC2
0
1
CC1
0
0
CC0
0
Figure 8-9. ATD Status Register 0 (ATDSTAT0)
Read: Anytime
Write: Anytime (No effect on (CC2, CC1, CC0))
Table 8-17. ATDSTAT0 Field Descriptions
Field
7
SCF
5
ETORF
4
FIFOR
2–0
CC[2:0]
Description
Sequence Complete Flag — This flag is set upon completion of a conversion sequence. If conversion
sequences are continuously performed (SCAN = 1), the flag is set after each one is completed. This flag can be
cleared when ADPU=1 and one of the following occurs:
A) Write “1” to SCF
B) Write to ATDCTL5 (a new conversion sequence is started)
C) If AFFC=1 and read of a result register
0 Conversion sequence not completed
1 Conversion sequence has completed
External Trigger Overrun Flag — While in edge trigger mode (ETRIGLE = 0), if additional active edges are
detected while a conversion sequence is in process the overrun flag is set. This flag can be cleared when
ADPU=1 and one of the following occurs:
A) Write “1” to ETORF
B) Write to ATDCTL2, ATDCTL3 or ATDCTL4 (a conversion sequence is aborted)
C) Write to ATDCTL5 (a new conversion sequence is started)
0 No External trigger over run error has occurred
1 External trigger over run error has occurred
FIFO Over Run Flag — This bit indicates that a result register has been written to before its associated
conversion complete flag (CCF) has been cleared. This flag is most useful when using the FIFO mode because
the flag potentially indicates that result registers are out of sync with the input channels. However, it is also
practical for non-FIFO modes, and indicates that a result register has been over written before it has been read
(i.e., the old data has been lost). This flag can be cleared when ADPU=1 and one of the following occurs:
A) Write “1” to FIFOR
B) Start a new conversion sequence (write to ATDCTL5 or external trigger)
0 No over run has occurred
1 An over run condition exists
Conversion Counter — These 3 read-only bits are the binary value of the conversion counter. The conversion
counter points to the result register that will receive the result of the current conversion. E.g. CC2 = 1, CC1 = 1,
CC0 = 0 indicates that the result of the current conversion will be in ATD result register 6. If in non-FIFO mode
(FIFO = 0) the conversion counter is initialized to zero at the begin and end of the conversion sequence. If in
FIFO mode (FIFO = 1) the register counter is not initialized. The conversion counters wraps around when its
maximum value is reached.
Aborting a conversion or starting a new conversion by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1.
MC3S12RG128 Data Sheet, Rev. 1.05
230
Freescale Semiconductor