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2.2 Headerless Packet Transmission Mode
By setting "Headerless packet transmission mode" on the REG03 register of the FDP02, the FDP02 transmits
packets by wireless transmission to a destination address that is defined by the REG02 register. At this mode,
a header part (command header "@", command "TXT" or "TBN", destination address, and number of message
bytes [for TBN command]) can be eliminated. The trigger of data transmission can be defined by the setting
of REG24 register. It can be selectable entering of "<Cr><Lf>" (0DH, 0AH) (i.e., carriage return and line
feed codes) or time over of the timeout period (a time gap limit between two data bytes that is set in the
REG26 register). Data transmission is triggered also when the number of message bytes exceeds 26 bytes.
It is also enable to set "Enabling response" and "Disabling response" mode in by the REG13 register at the
headerless packet transmission mode. Additionally, "Returning P1 and P0 responses" and "Returning P0
response" function can be selected when "Enabling response" mode is chosen. Moreover, "Enabling
destination address check at reception" and "Disabling destination address check at reception" function can be
selected by the REG18 register. For more details, see section 2.1 "Packet transmission mode".
Also, it is selectable whether "<Cr><Lf>" (0DH, 0AH) is added on the received data by the settings of the bit
4 of the REG23 register.
In headerless packet transmission mode, maximum data buffer size for sending
data is 130 bytes and data transmission is started when message data size exceeds
26 bytes. When many message data are input consequently, the message buffer
may be overflowed and the message data may be lost. At that situation, the
hardware flow control function should be set. If "Enabling response" function
is selected in REG13 register, it is possible to judge whether data transmission is
succeeded or not. Thus it is recommended to set "Enabling response" function
even in headerless packet mode.
Additionally, the massage data may be lacked when the size is over 26 bytes.
To prevent for such an event, check each response on the sender and create
messages so that the loss of packets can be detected on the receiver FDP02.
The serial communication speed of all FDP02 should be same setting. If
different serial communication speeds are set between on the sender and the
receiver FDP02, data loss may occur on the slower speed side.
3
Ver.1.1
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