Specifications

Cinterion
®
ELS81-US Hardware Interface Description
2.1 Application Interface
53
 els81-us_hid_v01.004 2017-09-27
Confidential / Preliminary
Page 21 of 107
SPI SPI_CLK O
V
OL
max = 0.25V at I = 1mA
V
OH
min = 1.55V at I = -1mA
V
OH
max = 1.85V
V
IL
max = 0.35V
V
IH
min = 1.30V
V
IH
max = 1.85V
If lines are unused keep
lines open.
Note that the SPI inter-
face lines are originally
available as GPIO lines.
If configured as SPI lines,
the GPIO lines are
assigned as follows:
GPIO3 --> SPI_CLK
GPIO16 --> MOSI
GPIO17 --> MISO
GPIO19 --> SPI_CS
MOSI O
MISO I
SPI_CS O
GPIO
interface
GPIO1-GPIO3 IO
V
OL
max = 0.25V at I = 1mA
V
OH
min = 1.55V at I = -1mA
V
OH
max = 1.85V
V
IL
max = 0.35V
V
IH
min = 1.30V
V
IH
max = 1.85V
Imax = ±5mA
If unused keep line open.
Please note that most
GPIO lines can be config-
ured by AT command for
alternative functions:
GPIO1-GPIO3: ASC0
control lines DTR0,
DCD0 and DSR0
GPIO4: Fast shutdown
GPIO5: Status LED line
GPIO6/GPIO7: PWM
GPIO8: Pulse Counter
GPIO16-GPIO19: ASC1
or SPI
GPIO24: ASC0 control
line RING0
GPIO4 IO
GPIO5 IO
GPIO6 IO
GPIO7 IO
GPIO8 IO
GPIO11-
GPIO15
IO
GPIO16-
GPIO19
IO
GPIO20-
GPIO23
IO
GPIO24 IO
Fast
shutdown
FST_SHDN I V
IL
max = 0.35V
V
IH
min = 1.30V
V
IH
max = 1.85V
~~|___|~~ low impulse width > 1ms
This line must be driven
low.
If unused keep line open.
Note that the fast shut-
down line is originally
available as GPIO line. If
configured as fast shut-
down, the GPIO line is
assigned as follows:
GPIO4 --> FST_SHDN
Status LED LED O
V
OL
max = 0.25V at I = 1mA
V
OH
min = 1.55V at I = -1mA
V
OH
max = 1.85V
If unused keep line open.
Note that the LED line is
originally available as
GPIO line. If configured
as LED line, the GPIO
line is assigned as fol-
lows:
GPIO5 --> LED
Table 2: Signal properties
Function Signal name IO Signal form and level Comment