Echelon FTXL - Manual (Page 110)

98 Developing an FTXL Application
FTXL Transceiver
Registered Memory
Window
Maximum range:
0x0001 – 0xFFFF
File directory
Template file
Writable value file
Read-only value file
unused
SNVT_address
File directory
Template file
Writable value file
Read-only value file
FTXL network address space
(Neuron addresses in big-endian
notation)
Virtual address space: defined host-side,
using virtual Smart Transceiver
addresses in host’s byte order
Physical host address space
Address translation provided by the Interface Developer;
address translation static (by correct declaration of
SNVT_address and file directory)
Address translation provided by Interface Developer
in FtxlDev.c; translation dynamic.
LON_DMF_WINDOW_START
L
O
N_DMF_W
INDOW_USAGE
Figure 12. Relationship between Different Memory Spaces
The LonTalk Interface Developer utility defines three macros in the generated
FtxlDev.h file for working with the DMF window:
• LON_DMF_WINDOW_START
• LON_DMF_WINDOW_SIZE
• LON_DMF_WINDOW_USAGE
The LON_DMF_WINDOW_USAGE macro helps you keep track of the DMF
window fill level. The LonTalk Interface Developer utility uses this value when
it registers the actual window, whereas LON_DMF_WINDOW_SIZE defines only
the maximum window size.
You can modify the DMF framework that the LonTalk Interface Developer utility
generates to include support for user-defined files. However, all of the data must
fit within the DMF memory window.
When your data exceeds the size of the DMF memory window, you must perform
one of the following tasks:
• Reduce the amount of data
• Implement the L
ON W ORKS File Transfer Protocol