PEB20534H-10 SIEMENS [Siemens Semiconductor Group], PEB20534H-10 Datasheet - Page 70

• Manufacturer Part Number: PEB20534H-10
• Description: DMA Supported Serial Communication Controller with 4 Channels DSCC4
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Semiconductor Group
The following figure provides an example, how a transmit descriptor and its associated
data buffer is located in the memory as a result of a memory dump.
Figure 14
Note: Although transmit descriptors consist of only 4 DWORDs it might be useful to
DSCC4 register CH0BTDA:
Base Transmit Descriptor Address Channel 0
31
31
Next Transmit Descriptor Ptr.=0x10001014
1
04
08
00
0
Transmit Data Pointer= 0x20000020
allocate 5 DWORD structures to achieve compatibility between transmit and
receive descriptors. In this case only small CPU performed manipulations are
necessary to convert a completed receive descriptor into a transmit descriptor re-
chained to a transmit descriptor list. This is typical e.g. for frame relay or bridging
applications where received data might be sent out again on another DSCC4 port.
0
CH0BTDA = 0x10001000
(dummy) 0x00000000
0x009
03
07
00
0x40000000
Transmit Descriptor Memory Example
02
06
00
01
05
09
0
0
70
FE Hold HI
DMA Controller and Central FIFOs
Host Memory Dump:
Value:
31
0x10090000
0x10010014
0x20000020
0x40000000
0x00000000
0x04030201
0x08070605
0x00000009
Data Sheet 09.98
PEB 20534
0
Address:
0x10001000
0x10001004
0x10001008
0x1000100C
0x10001010
0x10001014
0x20000020
0x20000024
0x20000028
0x20000030