C161U
Central Processor Unit
Preliminary Data Sheet
89
02.2000
PRELIMINARY
PRE
LI
M
INAR
Y
- E
XCE
RP
T
-
ONES (FF1E
H / 8FH)
SFR
Reset Value: FFFF
H
5.5
PEC - Extension of Functionality
Introduction
Compared to existing C16x architecture, the PEC transfer function is enhanced by
extended functionality. The extended PEC function is a further step into DMA control
functionality. It especially supports integrated system design with XBUS as system bus.
The extended PEC functions are defined as follows:
– Source pointer and destination pointer are extended to 23-bit pointer, thus enabling
PEC controlled data transfer between any two locations within the total address
space. Both 8-bit segment numbers of every source/destination pointer pair are
defined in one 16-bit SFR register; thus, 8 PEC segment number registers are
available for the 8 PEC channels.
– Two of the PEC channels are expanded by additional 16-bit transfer count registers;
when enabled, the original 8-bit bytecount in the control register serves as package
length count, thus defining the amount of bytes or words to be transferred with one
request. In C161U the package size is always limited to one transfer.
– For always two channels a chaining feature is provided. When enabled in the PEC
control register, a termination interrupt of one channel will automatically switch
transfer control to the other channel of the channel pair.
24-bit Extension of Source and Destination Pointers
The source and destination pointers specify the locations between which the data is to
be moved. For each of the eight PEC channels the source and destination pointers are
specified by one SFR register and two IRAM memory locations. One SFR register stores
the 8-bit segment number of the source (PECSSN) and the 8-bit segment number of the
destination (PECDSN) location in a respective 16-bit PEC Segment Number register
(PECSNx). The respective segment offset of source and destination are stored in IRAM
memory location identical to the IRAM locations of SRCPx and DSTPx pointers of Full-
Custom C16x standard PEC channels - thus the extension is fully compatible. With the
segment number extension of source and destination, data can be transferred by a PEC
transfer between any two locations within the 2 MByte address space of the C161U.
1
5
4
3
2
1
0
11
10
9
8
7
6
15
14
13
12
r
11
1
r
1
r