LTP5902-IPM_15 Datasheet, PDF (24/32 Pages) Linear Technology – SmartMesh IP Node 2.4GHz 802.15.4e Wireless Mote Module

LTP5901-IPM/LTP5902-IPM
Operation
Radio
Eterna includes the lowest power commercially available
2.4GHz IEEE 802.15.4e radio by a substantial margin.
(Please refer to the Radio Specifications section for
power consumption numbers.). Eterna’s integrated power
amplifier is calibrated and temperature compensated to
consistently provide power at a limit suitable for worldwide
radio certifications. Additionally, Eterna uniquely includes
a hardware-based autonomous MAC that handles precise
sequencing of peripherals, including the transmitter, the
receiver, and Advanced Encryption Standard (AES) pe-
ripherals. The hardware-based autonomous Media Access
Controller (MAC) minimizes CPU activity, thereby further
decreasing power consumption.
UARTs
The principal network interface is through the application
programming interface (API) UART. A Command-Line
Interface (CLI) is also provided for support of test and
debug functions. Both UARTs sense activity continuously,
consuming virtually no power until data is transferred over
the port and then automatically returning to their lowest
power state after the conclusion of a transfer. The defini-
tion for packet encoding on the API UART interface can
be found in the SmartMesh IP Mote API Guide and the
CLI command definitions can be found in the SmartMesh
IP Mote CLI Guide.
API UART Protocol
The API UART protocol was created with the goal of
supporting a wide range of companion Multipoint Control
Units (MCUs) while reducing power consumption of the
system. The receive half of the API UART protocol includes
two additional signals in addition to UART_RX: UART_RX_
RTSn and UART_RX_CTSn. The transmit half of the API
UART protocol includes two additional signals in addition
to UART_TX: UART_TX_RTSn and UART_TX_CTSn. The
API UART protocol is referred to as Mode 4.
In the Figures accompanying the protocol descriptions,
signals driven by the companion processor are drawn
in black and signals driven by Eterna are drawn in blue.
UART Mode 4
UART Mode 4 incorporates level sensitive flow control
on the TX channel and requires no flow control on the
RX channel, supporting 115200 baud. The use of level-
sensitive flow control signals enables higher data rates
with the option of using a reduced set of the flow control
signals; however, with the companion processor must
negate UART_TX_CTSn prior to the end of the packet and
wait at least t_{RX_RTS to RX_CTS} between sending packets.
See the UART AC Characteristics section for complete
timing specifications. Packets are HDLC encoded with
one stop bit and no parity bit. The use of the RX flow
control signals (UART_RX_RTSn and UART_RX_CTSn)
for Mode 4 are optional. The flow control signals for the TX
channel are shown in Figure 10. UART Mode 4 Transmit
Flow Control. Transfers are initiated by Eterna asserting
UART_TX_RTSn. The UART_TX_CTSn signal may be
actively driven by the companion processor when ready
to receive a packet or UART_TX_CTSn may be tied low
if the companion processor is always ready to receive a
packet. After detecting a logic ‘0’ on UART_TX_CTSn Eterna
sends the entire packet. Following the transmission of the
final byte in the packet Eterna negates UART_TX_RTSn
and waits for a minimum period defined in the UART AC
Characteristics section before asserting UART_TX_RTSn
UART_TX_RTSn
UART_TX_CTSn
UART_TX
BYTE 0
BYTE 1
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Figure 10. UART Mode 4 Transmit Flow Control
again.
For details on the timing of the UART protocol, see the
UART AC Characteristics section.
CLI UART
The Command Line Interface (CLI) UART port is a two
wire protocol (TX and RX) that operates at a fixed 9600
baud rate with one stop bit and no parity. The CLI UART
interface is intended to support command line instructions
and response activity.
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For more information www.linear.com/LTP5901-IPM or www.linear.com/LTP5902-IPM
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