SEC Controller
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
26-17
26.2.3.2 System Bus Master Read
When the controller is the bus master, a system bus read uses the following sequence:
1.
Channel asserts its bus read request to the controller.
2.
Channel furnishes external read address, internal write address, and transfer length.
3.
Controller sends request acknowledge to channel.
4.
Controller asserts request to the system bus through the master interface.
5.
Controller waits for system bus read to begin.
6.
When bus read begins, controller receives data from the master interface and performs a
write to the appropriate internal address supplied by the channel. Data may be realigned
byte-wise by the controller if either:
•
the read does not begin on a 32-bit boundary, or
•
the previous write to an execution unit input FIFO does not end on a 32-bit
boundary.
7.
Transfer continues until the bus read is completed and the controller has written all data
to the appropriate internal address. The master interface will continue making bus
requests until the full data length is read.
When the SEC performs a transaction as master, the intended slave can terminate the transfer due
to an error. The SEC transaction requests are posted to the device target queue, after which the
device takes responsibility for either completing the transaction or signalling an error. An error in
an SEC initiated transaction is also reported by the SEC via the Channel Interrupt Status Register
(CISR_n). The core processor can determine which channel generated the interrupt by checking
the ISR for the channel ERROR bit.
26.2.3.3 System Bus Master Write
When the controller is the system bus master, a system bus write uses the following sequence:
1.
Channel asserts its bus write request to the controller.
2.
Channel furnishes internal read address, external write address, and transfer length.
3.
Controller sends request acknowledge to the channel.
4.
Controller performs a read from the appropriate internal address supplied by the
channel, loads the write data into its FIFO, asserts a request to the system bus through
the master interface, and waits for the system bus to become available.
5.
When the system bus becomes available, controller writes data from its FIFO to the
master interface.
Even though the controller is handling a request from one channel, it can still acknowledge and
queue requests from the other channels.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...