SP2-433-160 Datasheet, PDF (12/27 Pages) Radiometrix Ltd – UHF SpacePort Transceiver

PS1
0
0
1
1
PS0
0
1
0
1
CONTINUOUS
POWER SAVE
SLEEP
OFF
20mA (no power saving)
programmable sleeptime *
< 460µA (fixed off time of 181ms)
< 50µA Transceiver is off ( reset or TXR to wake-up)
* Sleeptime programmable in EEPROM address 03h.
value
00
01
02
03
off -time
22ms
45ms
90ms
181ms
Average current
2.95 mA
1.60 mA
0.85 mA
0.46 mA
The supply current's quoted above are typical for a BiM2 + SP2 using the
EEPROM default values.
3.2 HTO & RTO - INTERFACE TIME-OUT
Both the Host and the Radio interfaces can 'hang' the SP2 while it
waits for an external event. Under error conditions the SP2 will reset
itself if the appropriate HTO or RTO switch is set.
RTO RADIO TIME OUT.
0 no time out
1 Time-Out and reset if > 2.9s of plain preamble detected. (note. valid extended
preamble used for wake-ups will not cause a Time-Out to be detected)
HTO HOST TIME OUT
0 no time out
1 Time-Out and reset if Host fails to reply to any request or handshake
within 2.9s
3.3 WE - EEPROM WRITE ENABLE
This bit protects the EEPROM from accidental writes, it must be set to 1 prior to each byte write to the
EEPROM (addresses 01h to 3Fh). This bit will be cleared by the SP2 after each byte write.
3.4 ST - RESERVED
Do not use. Reserved for future use.
3.5 LBT & DBT - COLLISION AVOIDANCE
Listen Before Transmit, LBT, and Delay Before Transmit, DBT determine what collision avoidance the
SP2 will take before each transmission.
LBT
0
0
1
1
DBT
0
1
0
1
Function
Immediate TX, no channel check
Fixed delay TX, no channel check (time slots)
This is useful for rapid polling of up to 255 units by a master station.
SLOTS is set to the units ID number, the packet size, preamble length and
change over delay must be the same for all units being polled.
see - EEPROM parameters
Immediate TX, if channel is clear
The receiver is turned on and the channel checked for preamble or data. The
SP2 will only go to transmit when the channel is clear.
Random delay TX, if channel is clear
This mode is useful in random access networks where there is a high statistical
probability that more than 2 SP2s could be attempting to transmit at the same
time. The receiver is turned on and the channel is checked for preamble or
data. If the channel is clear the SP2 will go to transmit, if the channel is busy
the SP2 will delay by a random time (setable by TX-BACK-OFF in EEPROM)
then try again for a clear channel.
Radiometrix Ltd, SP2 data sheet
page 12