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SL871 Family Product User Guide
1VV0301170 Rev. 9
Page 50 of 89
2021-07-15
Not Subject to NDA
RX1/SCL: This port accepts DGPS input using the RTCM SC-104 protocol or NMEA
commands.
Warning: The interface is changed via the $PMTK258 command.
Note that the module will reset when the interface is changed.
UART Port Operation
UART ports are full-duplex and support configurable baud rates.
Frame is 8 bits, no parity bit, and 1 stop bit.
The default rate of 9600 bps can be changed via the following commands -
Primary port: $PMTK251
Secondary port: $PMTK250
The idle state of UART interface lines is logic high.
The input and output levels are LVTTL compatible. See section 9.3.1 I/O Signal Levels.
UART TX logic levels are shown in Table 26: Output Logic Levels: TX and 1PPS.
UART RX logic levels are shown in Table 24: Input Logic Levels: RX and Reset-N, & Ant
Sense.
Warning: Note that the RX pins have a maximum input voltage of 3.4
V (which is lower than the maximum for Vcc or Vbatt).
Warning: Care must be used to prevent backdriving the RX lines when
the module is powered down or in a low-power state.
I2C Port Operation (SL871 and SL871L only)
The
secondary
port (SCA/RX1 & SDA/TX1) is I2C by default, but can be changed to UART
via command $
PMTK258.
The I
2
C_Clock and I
2
C_Data lines require external pullups (example value: 10 K
Ω
).
Note that the Ant_OC pin can be re-configured to be the Data Ready Indicator instead of
Antenna_Open.Contact Telit support for details.
Features
-
Содержание SL871
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