TDM Basics
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
19-27
the status bit. When the interrupt is asserted in the EPIC, then the SC3400 core can fill all the
transmit buffers from their beginnings to the byte to which the second threshold (TDBST) points.
Meanwhile, the TDM keeps reading new data from the buffer.
Figure 19-26 shows the threshold pointers for transparent and A/
μ
law channels.
The TDMxRDBFT[RDBFT], TDMxRDBST[RDBST], TDMxTDBFT[TDBFT], and
TDMxTDBST[TDBST] fields are control fields and can therefore be updated while the TDM is
active. For example, to invoke an interrupt for each 64 bits written to the system I/F memory, the
interrupt routine that handles the receive first threshold interrupt should include:
If (TDMxRDBFT[RDBFT] == (TDMxRDBS[RDBS] - 0xF))
then TDMxRDBFT[RDBFT] = 0x0
else if (TDMxRDBFT[RDBFT] == (TDMxRDBS[RDBS] - 0x7))
then TDMxRDBFT[RDBFT] = 0x8
else TDMxRDBFT[RDBFT] = TDMxRDBFT[RDBFT] + 0x10
The interrupt routine that handles the receive second threshold interrupt should include:
If (TDMxRDBST[RDBST] == (TDMxRDBS[RDBS] - 0xF))
then TDMxRDBST[RDBST] = 0x0
else if (TDMxRDBST[RDBST] == (TDMxRDBS[RDBS] - 0x7))
then TDMxRDBST[RDBST] = 0x8
else TDMxRDBST[RDBST] = TDMxRDBST[RDBST] + 0x10
Figure 19-26. Main Memory Buffers Threshold Pointers
Transparent Channel
A/
μ
Law Channel
Buf
fer Siz
e
RDBS/TDBS
First Threshold
Second Threshold
First Threshold
(RDBFT/TDBFT)
×
2
Second Threshold
(RDBST/TDBST)
×
2
Bu
ff
e
r Siz
e
2
×
RDBS / 2
×
TDBS
Displacement
RDBFT/TDBFT
RDBST/TDBST
TDBDR/RDBDR
Displacement
(TDBDR/RDBDR)
×
2
Data Buffer of
Data Buffer of
Содержание MSC8144E
Страница 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Страница 40: ...MSC8144E Reference Manual Rev 3 xl Freescale Semiconductor Contents 26 5 12 8 RNG Output FIFO 26 186 ...
Страница 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Страница 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Страница 167: ...OCE Event and JTAG Test Access Port Signals MSC8144E Reference Manual Rev 3 Freescale Semiconductor 3 59 ...
Страница 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Страница 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Страница 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Страница 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Страница 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Страница 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Страница 884: ...MSC8144E Reference Manual Rev 3 17 44 Freescale Semiconductor RapidIO Interface Dedicated DMA Controller ...
Страница 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...