2.2 BSP Rel. 1.0 for PPMC-275 Programmer's Guide
2.2 BSP Rel. 1.0 for PPMC-275 Programmer's Guide
2.2 BSP Rel. 1.0 for PPMC-275 Programmer's Guide
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
List of APIs API Call Reference<br />
Table 9:SDMA Driver Structure: TX_DESC<br />
Macro Field Bit<br />
Width<br />
Description<br />
UINT bytecnt 16 Byte count is the number<br />
of bytes to be transmitted.<br />
Zero byte counters<br />
are not supported with<br />
retransmission. Do not<br />
use zero byte buffers<br />
with LAP-D protocol.<br />
UINT Shadow 16 The CPU must initialize<br />
this field with a value<br />
identical to the Byte<br />
Count field. The MV-<br />
64360 subtracts the number<br />
of bytes actually<br />
transmitted from this<br />
parameter.<br />
Usually the MV-64360<br />
writes “0” in this field<br />
when closing a descriptor.<br />
However, when the<br />
transmit SDMA halts due<br />
to a transmit error, this<br />
number can be used to<br />
determine the number of<br />
bytes that were fetched<br />
into the MV-64360. Setting<br />
both the Byte Count<br />
and Shadow Byte Count<br />
to “0” will cause the<br />
SDMA to close the<br />
descriptor and move to<br />
the next descriptor, if<br />
both or neither of the F<br />
and L bits are set. Setting<br />
Byte Count and Buffer<br />
Size to “0” in transmit<br />
descriptors with one of<br />
the F or L bits set will<br />
lead to unpredictable<br />
behavior.<br />
TX_COMMAND cmd_sts 32<br />
5 - 52 VxWorks 5.5/Tornado <strong>2.2</strong> <strong>BSP</strong> <strong>Rel</strong>. <strong>1.0</strong> <strong>for</strong> <strong>PPMC</strong>-<strong>275</strong>
Change language