Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
19-14 Freescale Semiconductor
NOTE
The eQADC null message send format register (eQADC_NMSFR) only
defines the format of the null message that eQADC sends. The null message
register does not control how the eQADC detects a null message from the
input source. The eQADC detects a null message by decoding the
MESSAGE_TAG field on the receive data. Refer to Table 19-34 for more
information on the MESSAGE_TAG field.
NOTE
Writing to the eQADC null message send format register while serial
transmissions are enabled is not recommended. Refer to
EQADC_MCR[ESSIE] field in Section 19.3.2.1, “eQADC Module
Configuration Register (EQADC_MCR).”
19.3.2.3 eQADC External Trigger Digital Filter Register (EQADC_ETDFR)
The EQADC_ETDFR is used to set the minimum time a signal must be held in a logic state on the CFIFO
triggers inputs to be recognized as an edge or level gated trigger. The digital filter length field specifies the
Address: Base + 0x0008 Access: R/W
0123456789101112131415
R000000
NMF
W
Reset0000000000000000
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R
NMF
W
Reset0000000000000000
Figure 19-3. eQADC Null Message Send Format Register (EQADC_NMSFR)
Table 19-4. EQADC_NMSFR Field Descriptions
Field Description
0–5 Reserved.
6–31
NMF
[0:25]
Null message format. Contains the programmable null message send value for the eQADC. The value written to this
register is sent as a null message when serial transmissions from the eQADC SSI are enabled (ESSIE field is
configured to 0b11 in EQADC_MCR (Section 19.3.2.1, “eQADC Module Configuration Register (EQADC_MCR))
and either
• there are no triggered CFIFOs with commands bound for external command buffers, or;
• there are triggered CFIFOs with commands bound for external command buffers but the external command
buffers are full.
Refer to Section , “Null Message Format for External Device Operation” for more information on the format of a null
message.
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