RFM23
8.8. 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.
POR
Def.
Function/D
escription
GPIO0
D7
D6
D5
D4
D3
D2
D1
D0
Add R/W
R/W
gpio0
gpio0dr
v[0]
gpio0[4] gpio0[3] gpio0[2] gpio0[1] gpio0[0]
gpio1[4] gpio1[3] gpio1[2] gpio1[1] gpio1[0]
gpio2[4] gpio2[3] gpio2[2] gpio2[1] gpio2[0]
pup0
Pup1
Pup2
00h
00h
00h
00h
0B
Configuration drv[1]
GPIO1 Gpio1
Configuration drv[1]
GPIO2 Gpio2
R/W
gpio1dr
v[0]
0C
R/W
gpio2dr
v[0]
0D
Configuration drv[1]
I/O Port
extitst[2] extitst[ extitst[0] itsdo
1]
dio2
dio1
dio0
R/W
0E
Configuration
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
00000—Default Setting
POR
GPIO0
GPIO1
GPIO2
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,‖.
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