MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 509

• Manufacturer Part Number: MMC2114
• Description: M CORE Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

19.10.11 Result Word Table
19.11 Pin Connection Considerations
19.11.1 Analog Reference Pins
MMC2114 • MMC2113 • MMC2112 — Rev. 1.0
MOTOROLA
NOTE:
The result word table is a 64 half-word (128 byte) long by 10-bit wide
RAM. An entry is written by the QADC after completing an analog
conversion specified by the corresponding CCW table entry. The result
word table can be read or written, but in normal operation is only read to
obtain analog conversions from the QADC. Unimplemented bits read as
0s and writes have no effect.
Although the result RAM can be written, some write operations, like bit
manipulation, may not operate as expected because the hardware
cannot access a true 16-bit value.
While there is only one result word table, the half-word (16-bit) data can
be accessed in three different data formats:
The left justified, signed format corresponds to a half-scale, offset binary,
two’s complement data format. The address used to read the result table
determines the data alignment format. All write operations to the result
word table are right justified.
The QADC requires accurate, noise-free input signals for proper
operation. This section discusses the design of external circuitry to
maximize QADC performance.
No A/D converter can be more accurate than its analog reference. Any
noise in the reference can result in at least that much error in a
conversion. The reference for the QADC, supplied by pins V
should be low-pass filtered from its source to obtain a noise-free, clean
signal. In many cases, simple capacitive bypassing may suffice. In
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Freescale Semiconductor, Inc.
For More Information On This Product,
Queued Analog-to-Digital Converter (QADC)
Right justified with 0s in the higher order unused bits
Left justified with the most significant bit inverted to form a sign bit,
and 0s in the unused lower order bits
Left justified with 0s in the lower order unused bits
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Queued Analog-to-Digital Converter (QADC)
Pin Connection Considerations
Advance Information
RH
and V
RL
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