I 2 C; Voltage Reference; Reset; Table 48. I 2 C Interface Pads - Sierra Wireless AirPrime AR7558 Hardware Integration Manual

Hardware Integration Guide
2
6.10. I C
The AirPrime AR7558 provides an I
2
Table 48. I C Interface Pads
Pad Name
CD6 I2C_CLK
CC6 I2C_SDA
2
The I C signals are open drain outputs with 2.2 kΩ pull-up resistors to VCC_1V8 internal to the
AirPrime AR7558.

6.11. Voltage Reference

The AirPrime AR7558 utilizes 1.8V logic. A voltage reference output for this rail is provided below.
Table 49. Voltage Reference Pad
Pad Name
AA12 VCC_1V8
AB12 VCC_1V8
Table 50. Voltage Reference Characteristics
Parameter
Voltage Level
VCC_1V8
Output Current
The VCC_1V8 signal can be used to power external circuitry and/or detect the power state of the
AirPrime AR7558 device.
Using VCC_1V8 to determine the power state is recommended when the user application wants to
disable VBATT. VBATT should not be disabled before VCC_1V8 goes inactive. To be able to detect
the power state on VCC_1V8, all logic input signals to the AirPrime AR7558device must be set low
(see Digital IO Characteristics
The VCC_1V8 signal is High-Z when the AirPrime AR7558 embedded module is powered down.

6.12. RESET

The AirPrime AR7558 provides an interface to allow an external application to RESET the module as
well as an output to indicate the current RESET state or control an external device.
Table 51. Reset Interface Pads
Pad Name
AH2 RESIN_N
AG4 RESOUT_N
4116922
2
C interface.
Direction Function
Output I2C Clock output
Input/Output I2C Data
Direction
Output
Output
for affected signal groups).
Direction Function
Input External Reset Input
Output Reset Output
Rev 1.1
Function
Voltage Reference Output
Voltage Reference Output
Min Typ
1.746 1.8
Baseband Specification
If Unused
Leave Open
Leave Open
If Unused
Leave Open
Leave Open
Max Units
1.854 V
25 mA
If Unused
Leave Open
Leave Open
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