Smartrek Technologies 900 MHz Mesh Network Long Range Transceiver Module : Integration Guide : Page 34

SMK900 Integration Guide Revision 4

hopTable

holds the current hop sequence of the network intended to be connected to the transceiver. This

variable ranges from 0 to 5 (i.e. 6 different possible values). Combined with nwkID,

cryptoData_qWord0 and cryptoData_qWord1, this defines a unique network access key. Note that if

one discounts the use of encryption keys, then it would be possible to combine hopTable and nwkID

in such a way that the combined number becomes an extended "channel number". For instance, one

could define an arbitrary configuration variable CHANNEL with the following mapping: hopTable

= CHANNEL % 6 + HOPTABLE_OFFSET, and nwkID = CHANNEL % 8 + NWKID_OFFSET, where

HOPTABLE_OFFSET and NWKID_OFFSET are arbitrarily chosen numbers. This would extend the

maximum number of channels to effective

power

holds two different power presets, one at high power (1 = HI: 158mW) and the other at low power

(0 = LO: 40mW).

uart_bsel

baud rate selector register for the main UART communication bus. See section 3.0 for details on

how to configure this register.

nodeType

defines the type of transceiver, which can either be a gateway (nodeType = 0) or an individual node of

the mesh (nodeType = 1).

sleepMode

selects the active sleep clock in use with the transceiver. Idle mode (sleepMode = 0) is a setting where

only the internal fast clock of the mesh controller is employed as the main sleep time base.

WARNING: this setting is the highest power consumption mode, and is mainly suitable for

transceivers wired on the electrical grid in some way, with high power availability off-grid.

Examples include typically transceivers configured as gateways. RC mode (sleepMode = 1) is a setting

where a lower power RC clock is used as the main sleep clock... This mode uses the higher-speed

clock in order to recalibrate the RC clock operation from broadcast cycle to broadcast cycle, in order

to compensate for clock frequency variation due to environmental changes such as temperature.

Note that even with this compensation in place, it is not suggested to use this sleep mode for sleep

intervals between broadcast cycles higher than 2 seconds. Finally, external sleep controller mode

(sleepMode = 2) allows the use of a dedicated Smartrek external sleep controller chip in I2C slave

mode in order to retro-fit ultra-low power consumption capabilities for longer sleep period of times

(> 2 seconds, up to about 20 seconds). This chip is to be connected to the main transceiver using the

transceiver I2C lines. Pull-up resistor values suggested for that I2C bus is 2 kOhms or less, and

powered with an input voltage between 3.3 and 5.5 V. See section 6.3 for more details on how to

integrate the external sleep controller chip.

extSlpCtrlI2CAddress

external sleep controller I2C address, if external sleep controller is selected as the main sleepMode

mode of operation. Default factory-configured I2C address is 0x48 (note that the external sleep

controller itself can have its own internal address changed via I2C command (see section 6.3 for

more details).

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