MPC555
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MPC556
QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
13-2
13.2 Features
Each QADC64 module offers the following features:
• Internal sample and hold
• Up to 16 analog input channels using internal multiplexing
• Directly supports up to four external multiplexers (for example, the MC14051)
• Up to 41 total input channels with internal and external multiplexing
• Programmable input sample time for various source impedances
• Two conversion command queues with a total of 64 entries
• Sub-queues possible using pause mechanism
• Queue complete and pause software interrupts available on both queues
• Queue pointers indicate current location for each queue
• Automated queue modes initiated by:
— External edge trigger [queues 1 and 2] and gated mode [queue 1 only]
— Periodic/interval timer, within QADC64 module [queues 1 and 2]
— Software command [queues 1 and 2]
• Single-scan or continuous-scan of queues
• 64 result registers
• Output data readable in three formats:
— Right-justified unsigned
— Left-justified signed
— Left-justified unsigned
• Unused analog channels can be used as digital ports
13.3 QADC64 Pin Functions
The two QADC64 modules use the following 38 pins:
• Two analog reference pins, to which all analog input voltages are scaled (shared
by the two modules)
• 32 analog input pins (16 per module, with three analog inputs per module multi-
plexed with multiplex address signals)
• Two analog power pins (shared by the two modules)
• Two external trigger pins (shared by the two modules)
The 16 channel/port pins in either module can support up to 41 channels when exter-
nal multiplexing is used (including internal channels). All of the channel pins can also
be used as general-purpose digital port pins.
The following paragraphs describe QADC64 pin functions.
shows the
QADC64 module pins.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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