mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 215

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

6.3.2.4
This register controls the conversion sequence length, FIFO for results registers and behavior in Freeze
Mode. Writes to this register will abort current conversion sequence but will not start a new sequence.
Read: Anytime
Write: Anytime
Freescale Semiconductor
Reset
FRZ[1:0]
Field
FIFO
S8C
S4C
S2C
S1C
1:0
W
6
5
4
3
2
R
ATD Control Register 3 (ATDCTL3)
0
0
7
Conversion Sequence Length — This bit controls the number of conversions per sequence.
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
Conversion Sequence Length — This bit controls the number of conversions per sequence.
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
Conversion Sequence Length — This bit controls the number of conversions per sequence.
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
Conversion Sequence Length — This bit controls the number of conversions per sequence.
all combinations. At reset, S4C is set to 1 (sequence length is 4). This is to maintain software continuity to HC12
Family.
Result Register FIFO Mode —If this bit is zero (non-FIFO mode), the A/D conversion results map into the
result registers based on the conversion sequence; the result of the first conversion appears in the first result
register, the second result in the second result register, and so on.
If this bit is one (FIFO mode) the conversion counter is not reset at the beginning or ending of a conversion
sequence; sequential conversion results are placed in consecutive result registers. In a continuously scanning
conversion sequence, the result register counter will wrap around when it reaches the end of the result register
file. The conversion counter value (CC3-0 in ATDSTAT0) can be used to determine where in the result register
file, the current conversion result will be placed.
Aborting a conversion or starting a new conversion by write to an ATDCTL register (ATDCTL5-0) clears the
conversion counter even if FIFO=1. So the first result of a new conversion sequence, started by writing to
ATDCTL5, will always be place in the first result register (ATDDDR0). Intended usage of FIFO mode is
continuos conversion (SCAN=1) or triggered conversion (ETRIG=1).
Finally, which result registers hold valid data can be tracked using the conversion complete flags. Fast flag clear
mode may or may not be useful in a particular application to track valid data.
0 Conversion results are placed in the corresponding result register up to the selected sequence length.
1 Conversion results are placed in consecutive result registers (wrap around at end).
Background Debug Freeze Enable — When debugging an application, it is useful in many cases to have the
ATD pause when a breakpoint (Freeze Mode) is encountered. These 2 bits determine how the ATD will respond
to a breakpoint as shown in
may compromise the accuracy of an immediately frozen conversion depending on the length of the freeze
period.
= Unimplemented or Reserved
S8C
0
6
Figure 6-6. ATD Control Register 3 (ATDCTL3)
Table 6-8. ATDCTL3 Field Descriptions
S4C
MC9S12E256 Data Sheet, Rev. 1.08
Table
1
5
6-10. Leakage onto the storage node and comparator reference capacitors
S2C
0
4
Description
S1C
Chapter 6 Analog-to-Digital Converter (ATD10B16CV4)
3
0
FIFO
0
2
FRZ1
0
1
Table 6-9
Table 6-9
Table 6-9
Table 6-9
FRZ0
0
0
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