ks8701 Samsung Semiconductor, Inc., ks8701 Datasheet - Page 62

• Manufacturer Part Number: ks8701
• Description: Flextm Roaming Decoder Ii
• Manufacturer: Samsung Semiconductor, Inc.

KS8701
BUILDING A FRAGMENTED MESSAGE
characters per word yields a maximum message of 252 characters in a frame assuming no other traffic.
Messages longer than this value must be sent as several fragments.
pager to examine every following frame for an additional fragment until the last fragment with the continue bit
reset is found. The only requirement relating to the placement in time of the remaining fragments is that no more
than 32 frames (1 minute) or 128 frames (4 minutes) as indicated by the service provider may pass between
fragment receptions.
to detect missing fragments, a message number to identify which message the fragment is a part, and the
continue bit which either indicates that more fragments are in queue or that the last fragment has been received.
fragmented message:
The longest message which will fit into a frame is 84 code words total of message data. Three alpha
Additional fragments can be expected when the “continue bit” in the 1
Each fragment contains a check sum character to detect errors in the fragment, a fragment number 0, 1, or 2
The following describes the sequence of events between the Host and the KS8701 required to handle a
l
l
l
l
l
The host will receive a vector indicating one of the following types:
The KS8701 will increment the all frame mode counter inside the KS8701 and begin to decode all of the
following frames.
The host will receive the Message Packet(s) contained within that frame followed by a Status Packet.
The host must decide based on the Message Packet to return to normal decoding operation. If the
message is indicated as fragmented by the Message Continued Flag “C” being set in the Message
Packet then the host does not decrement the all frame mode counter at this time. The host decrements
the counter if the Message Continued Flag “C” is clear by writing the All Frame Mode Packet to the
KS8701 with the “DAF” bit = 1. If no other fragments, temporary addresses are pending and the FAF bit
is clear in the All Frame Mode Register, then the KS8701 returns to normal operation.
The KS8701 continues to decode all of the frames and passes any address information, vector
information and message information to the host followed by a status packet indicating the end of the
frame. If the message is indicated as fragmented by the Message Continued Flag “C” in the Message
Packet then the host remains in the receive mode expecting more information from the KS8701.
After the host receives the second and subsequent fragment with the Message Continued Flag “C” = 1,
it should decrement the all frame mode counter by sending an All Frame Mode Packet to the KS8701
with the “DAF” bit = 1. Alternatively, the host may choose to decrement the counter at the end of the
entire message by decrementing the counter once for each fragment received.
V
2
000
101
110
V
1
V
FLEX
0
TM
Roaming Decoder II
Alphanumeric
Hex / Binary
Secure
Type
st
Message Word is set. This causes the
Appendix A: Application Notes
61