
Enhanced Queued Analog-to-Digital Converter (EQADC)
MPC5644A Microcontroller Reference Manual, Rev. 6
1094
Freescale Semiconductor
The purpose of this bit is to mark in the command queue, where to start a repeating sequence. This location
is stored in an additional pointer ‘Repeat Pointer’.
Streaming mode requires 2 trigger inputs. The standard queue 0 trigger, in this mode referred to as Repeat
Trigger and a new internal trigger input to the eQADC called Advance Trigger (no filter available).
CFIFO0 is configured to operate in streaming mode by setting the bit STRME0 as described in
Section 25.5.2.7, EQADC CFIFO Control Registers (EQADC_CFCR)
. CFIFO0 is eight entries deep in
extended mode by setting the bit CFEEE0 in the same EQADC_CFCR register, and each entry is 32 bits
long. This CFIFO0 serves as a local storage of a few commands that need to be executed sequentially as
in a FIFO but can contain sub-queues that need to be executed several times. The CFFF0 bit in
Section 25.5.2.9, EQADC FIFO and Interrupt Status Registers (EQADC_FISR)
, is used to assure the
CFIFO0 is not full and command messages are stored from address 0x0 to 0x7.
25.6.4.2.1
CFIFO0 Operation in Streaming Mode
In Streaming mode, the CFIFO0 is filled with CCWs using the DMA exactly the same as existing modes.
The CFIFO executes commands as per the existing modes until it executes a Conversion Command Word
with the Repeat bit set. When this CCW is executed, the Repeat Pointer is set to point to this FIFO location
and from this CCW onwards, CFIFO0 entries is not invalidated, that is, the Repeat Pointer prevents this
and subsequent entries from being overwritten.
The queue continues to execute until a CCW with an asserted Pause bit is completed; then the queue stops
and enters the Pause state, waiting for a trigger. This is the same as normal behavior.
The Pause state is exited in one of two ways: Repeat Trigger or Repeat Trigger with Advance Trigger. The
Repeat trigger with no Advance trigger causes the Transfer Next Data Pointer to be loaded with the Repeat
Pointer location and CCWs are then executed from the Repeat Pointer back to the Pause bit. This means
that a section of the CFIFO0 is repeatedly executed every time a Repeat Trigger occurs.
The Repeat trigger with the Advance trigger pending causes all CCWs from the Repeat pointer to the Pause
bit to be invalidated and the CCW after the pause bit to be executed. This is achieved by invalidating the
Repeat Pointer. The effect is that the queue advances beyond the repeating section of the CFIFO0 to
execute new CCWs.
Note that the Advance trigger can occur at any time between Repeat triggers, but is only actioned when
the next Repeat trigger occurs. Prior to that it is pending.
In a typical application, the queue is made of some configuration commands to the ADC (to flush the
decimator or turn on pad pull-up/down) followed by a repeating section of ADC conversions on one or
more ADC channels from one or more sensors; followed by a few more configuration commands; then
more repeating ADC conversions, until the entire engine cycle is complete; when the queue is restarted.
The mechanism described permits any number of repeating sub-queues to be loaded and executed,
interspersed by configuration commands.
25.6.4.2.2
Triggering Description in Streaming Mode
The additional trigger signal ATRIG0 is detected by a separate circuit that is configured by the bit field
AMODE0 as described in
Section 25.5.2.7, EQADC CFIFO Control Registers (EQADC_CFCR)
trigger signal is used as an advance control of pop pointer of CFIFO0. In addition, it is used as the enable
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...