MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor 19-59
19.4.2 Command/Result Queues
The command and result queues are actually part of the eQADC system although they are not hardware
implemented inside the eQADC. Instead command and result queues are user-defined queues located in
system memory. Each command queue entry is a 32-bit command message.The last entry of a command
queue has the EOQ bit asserted to indicate that it is the last entry of the queue. The result queue entry is a
16-bit data item.
See Section 19.1.4, “Modes of Operation,” for a description of the message formats and their flow in
eQADC.
Refer to Section 19.5.5, “Command Queue and Result Queue Usage,” for examples of how command
queues and result queues can be used.
0123456789101112131415
CONTENTS OF EQADC_NMSFR REGISTER
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
CONTENTS OF EQADC_NMSFR REGISTER
Figure 19-33. Null Message Send Format for External Device Operation
0123456789101112131415
Reserved MESSAGE_TAG
(0b1000)
BUSY1 BUSY0
RFIFO Header
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
DETERMINED BY THE EXTERNAL DEVICE
ADC Result
Figure 19-34. Null Message Receive Format for External Device Operation
Table 19-43. Null Message Receive Format for External Device Operation
Bits Name Description
6–7 — Reserved.
8–11 MESSAGE_TAG[
0:3]
MESSAGE_TAG field. Refer to Section , “ Conversion Command Message Format for
On-Chip ADC Operation.”
12–15 BUSYn
[0:1]
BUSY status. Refer to Section , “ Result Message Format for External Device Operation.”
16–31 — Determined by the external device.
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