ADSP-2126x SHARC Processor Hardware Reference
7-13
I/O Processor
Transfer Control Block Chain Loading (TCB)
During TCB chain loading, the I/O processor loads the DMA channel
parameter registers with values retrieved from internal memory. The
address in the chain pointer register points to the highest address of the
TCB (containing the index parameter). This means that if a program
declares an array to hold the TCB, the
CP
register should not point to the
first location of the array. Instead the
CP
register should point to
array[3]
.
shows the TCB-to-register loading sequence for the serial port
and SPI port DMA channels. The I/O processor reads each word of the
TCB and loads it into the corresponding register. Programs must set up
the TCB in memory in the order shown in
parameter at the address pointed to by the
CP
register of the previous
DMA operation of the chain. The end of the chain (no further TCBs are
loaded) is indicated by a TCB with a
CP
value of zero.
A TCB chain load request is prioritized like all other DMA operations.
The I/O processor latches a TCB loading request and holds it until the
load request has the highest priority. If multiple chaining requests are
present, the I/O processor services the
TCB
registers for the highest priority
DMA channel first. A channel that is in the process of chain loading
Table 7-2. TCB Chain Loading Sequence
1
1 Chaining is not available using the IDP or parallel ports.
Address
2
2 An “x” denotes the DMA channel used. While the TCB is eight locations
in length, SPI and serial ports only use the first four locations.
Serial Ports
SPI Port
CPSPx + 0x0008 0000
IISPx
IISPI
CPSPx – 1 + 0x0008 0000
IMSPx
IMSPI
CPSPx – 2 + 0x0008 0000
CSPx
CSPI
CPSPx – 3 + 0x0008 0000
CPSPx
CPSPI
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...