TinyOS has two 802.15.4 frame formats. The first format, the T-Frame, is for TinyOS networks which do not share their channel with other wireless -networking archtiectures. This frame format assumes that TinyOS can use +networking architectures. This frame format assumes that TinyOS can use every bit of the packet and does not need to state that it is a TinyOS packet. T-Frame stands for "TinyOS Frame."
The TinyOS 802.15.4 T-frame format is as follows:
@@ -361,22 +361,26 @@ for "Interoperable Frame." | 802.15.4 Header | 6lowpan | AM type | data | 802.15.4 CRC | +-------------------+---------+------------------------------+--------------+ -AM type is the same as in a T-frame. 6lowpan is the IANA-assigned code -to identify this as a TinyOS packet. At this time, the exact value of -this code has not been determined. To inform 6lowpan that this is not -a 6lowpan packet, the code used MUST be in the range of 192-55.
-The AM type 6lowpan is reserved. A TinyOS program MUST NOT use it.
+AM type is the same as in a T-frame. 6lowpan is the NALP code to +identify this as a TinyOS packet. NALP codes must be in the range of +0-63. TinyOS uses code 63 (0x3F).
+The AM type 63 is reserved for both T-Frames and I-Frames. A TinyOS +program MUST NOT use it.
An implementation of the T-Frame can be found in tinyos-2.x/tos/chips/cc2420.
-An implementation of the I-Frame will soon be found in -tinyos-2.x/tos/chips/cc2420.
+An implementation of T-Frames and I-Frames can be found in +tinyos-2.x/tos/chips/cc2420/. The components in +tos/chips/cc2420/lowpan/ control which is used. By default, TinyOS +802.15.4 stacks use I-Frames, and the 'tframe' make option configures +them to use T-Frames. This make option defines a symbol named +TFRAMES_ENABLED. In the case of the CC2420 stack, this causes +CC2420.h to define CC2420_IFRAME_TYPE, which adds the extra +byte to the message_t header structure.