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Enhanced Serial Communication Interface (ESCI)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
1371
If the application disabled the receiver by clearing the receiver enable bit RE in the
Status Register 1 (eSCI_IFSR1)
the current frame is discarded and no flags will be updated.
31.4.5.3.10
DMA controlled SCI data frames reception
In this mode, the eSCI module controls the reception of SCI Data frames automatically and utilizes the
connected DMA channels. A block diagram which presents an overview of the DMA Controlled SCI Data
Frame reception is shown in
. The RX DMA channel is used to transfer the received frame
data into the memory.
When new data was received, the module generates the receive DMA request and the DMA controller
retrieves the provided data from the
. The read access from the low byte of
signals the end of the DMA cycle for the current data and triggers the
reception of new data. The read access from the
triggers no internal action.
The application request the eSCI module to enter this mode by setting the RXDMA bit in the
. From this point in time, the module start the generation of DMA requests and frame
transmission and reception. Before entering this mode, the application should perform the following
actions:
1. Configure the module for SCI mode.
2. Enable the receiver by setting RE in
3. Setup the DMA controller channel.
Figure 31-31. DMA Controlled SCI Data Frame Reception
31.4.5.3.11
Receiver overrun
When the eSCI module has received a frame and attempts to transfer the payload data of the received frame
into the
but neither the application nor the DMA controller has read the
since its last update, the overrun flag OR in the
Interrupt Flag and Status Register
received data are lost.
DMA
Controller
eSCI
System Memory
DATA 1
DATA N
SCI Data frame
RX DMA
channel
DATA 2
DATA N
DATA 1
Summary of Contents for MPC5644A
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Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
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Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
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