RFM42 Datasheet, PDF (43/110 Pages) –

RFM42/43
7.7. GPIO Configuration
Three general purpose IOs (GPIOs) are available. Numerous functions such as specific interrupts, TRSW control,
Microcontroller Output, etc. can be routed to the GPIO pins as shown in the tables below. When in Shutdown mode
all the GPIO pads are pulled low.
Note: The ADC should not be selected as an input to the GPIO in Standby or Sleep Modes and will cause excess
current consumption.
Function/D
POR
Add R/W
D7
D6
D5
D4
D3
D2
D1
D0
escription
Def.
R/W
0B
GPIO0
gpio0 gpio0dr
gpio0[4] gpio0[3] gpio0[2] gpio0[1] gpio0[0]
pup0
00h
Configuration drv[1] v[1]
R/W
0C
wt
gpio1[4] gpio1[3] gpio1[2] gpio1[1] gpio1[0]
GPIO1
Gpio1
gpio1dr Pup1
00h
Configuration drv[1]
v[1]
R/W
0D
w
gpio2[4] gpio2[3] gpio2[2] gpio2[1] gpio2[0]
GPIO2
Gpio2
gpio2dr Pup2
00h
Configuration drv[1]
v[1]
I/O Port
0E R/W
Configuration
extitst[2] extitst[ extitst[0] itsdo
dio2
dio1
dio0
00h
1]
The GPIO settings for GPIO1 and GPIO2 are the same as for GPIO0 with the exception of the 00000 default
setting. The default settings for each GPIO are listed below:
GPIO
GPIO0
GPIO1
GPIO2
00000—Default Setting
POR
POR Inverted
Microcontroller Clock
The module is configured to provide the System Clock output to the microcontroller so that only one crystal is needed
in the system, therefore reducing the BOM cost. For the TX Data Source, Direct Mode is used because long packets
are desired with a unique packet handling format already implemented in the microcontroller. In this configuration the
TX Data Clock is configured onto GPIO0, the TX Data is configured onto GPIO1, and the Microcontroller System Clock
output is configured onto GPIO2.
For a complete list of the available GPIO's see ―Register 0Ch. GPIO Configuration 1,‖, ―Register 0Dh.
GPIO Configuration 2,‖, and ―Register 0Eh. I/O Port Configuration,‖.
43
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