
Enhanced Queued Analog-to-Digital Converter (EQADC)
MPC5644A Microcontroller Reference Manual, Rev. 6
1088
Freescale Semiconductor
Null Message Format for External Device Operation
Null Messages are only transferred through the serial interface to allow results and unsolicited control data,
like the status of the external CBuffers, to return when there are no more commands pending to transfer.
Null Messages are only transmitted when serial transmissions from the EQADC SSI are enabled (See
ESSIE field in
Section 25.5.2.1, EQADC Module Configuration Register (EQADC_MCR)
”), and when
one of the following conditions apply:
1. there are no triggered CFIFOs with commands bound for external CBuffers, or;
2. there are triggered CFIFOs with commands bound for external CBuffers but the external CBuffers
are full. The EQADC detected returning BUSYx fields indicating “Do not send commands”.
illustrates the null message send format. When the EQADC transfers a null message, it
directly shifts out the 26-bit data content inside the
Section 25.5.2.3, EQADC null message send format
. The register must be programmed with the null message send format of the
external device.
illustrates the null message receive format. It has the same fields found in a Result Message
with the exception that the ADC result is not used. Refer to
Section , Result Message Format for External
, for more information. The MESSAGE_TAG field must be set to the Null Message tag
(0b1000). The EQADC does not store into an RFIFO any incoming message with a Null Message tag.
Table 25-61. Command BUFFERx BUSY Status
BUSYx[0:1]
Meaning
0b00
Send available commands - CBuffer is empty
0b01
Send available commands
0b10
Send available commands
0b11
Do not send commands
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
RESERVED
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 25-58. Null Message Send Format for External Device Operation
Содержание MPC5644A
Страница 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Страница 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Страница 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Страница 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Страница 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Страница 130: ...Device Performance Optimization MPC5644A Microcontroller Reference Manual Rev 6 130 Freescale Semiconductor...
Страница 204: ...Multi Layer AHB Crossbar Switch XBAR MPC5644A Microcontroller Reference Manual Rev 6 204 Freescale Semiconductor...
Страница 212: ...Peripheral Bridge PBRIDGE MPC5644A Microcontroller Reference Manual Rev 6 212 Freescale Semiconductor...
Страница 558: ...System Integration Unit SIU MPC5644A Microcontroller Reference Manual Rev 6 558 Freescale Semiconductor...
Страница 582: ...Frequency modulated phase locked loop FMPLL MPC5644A Microcontroller Reference Manual Rev 6 582 Freescale Semiconductor...
Страница 766: ...Enhanced Time Processing Unit eTPU2 MPC5644A Microcontroller Reference Manual Rev 6 766 Freescale Semiconductor...
Страница 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Страница 1236: ...System Information Module and Trim SIM MPC5644A Microcontroller Reference Manual Rev 6 1236 Freescale Semiconductor...
Страница 1250: ...Cyclic Redundancy Checker CRC Unit MPC5644A Microcontroller Reference Manual Rev 6 1250 Freescale Semiconductor...
Страница 1336: ...Deserial Serial Peripheral Interface DSPI MPC5644A Microcontroller Reference Manual Rev 6 1336 Freescale Semiconductor...
Страница 1388: ...Enhanced Serial Communication Interface ESCI MPC5644A Microcontroller Reference Manual Rev 6 1388 Freescale Semiconductor...
Страница 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...
Страница 1624: ...FlexRay Communication Controller FlexRay MPC5644A Microcontroller Reference Manual Rev 6 1624 Freescale Semiconductor...
Страница 1670: ...JTAG Controller JTAGC MPC5644A Microcontroller Reference Manual Rev 6 1670 Freescale Semiconductor...
Страница 1692: ...Nexus Port Controller NPC MPC5644A Microcontroller Reference Manual Rev 6 1692 Freescale Semiconductor...
Страница 1701: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 Freescale Semiconductor 1701...
Страница 1702: ...Development Trigger Semaphore DTS MPC5644A Microcontroller Reference Manual Rev 6 1702 Freescale Semiconductor...