Renesas RL78 Series User Manual page 628

RL78/G1D
15.2 Pin Functions
15.2.1 Digital pins
The digital pins of the RF transceiver are shown below.
For pin status in operation modes of RF transceiver, see 15.4.5 Pin status in each mode.
(1) CLKOUT_RF
This is the output pin for a clock signal.
Output on this pin can be disabled or it can produce a clock signal at 16 MHz, 8 MHz, or 4 MHz obtained by
frequency-dividing the 32-MHz RF base clock.
The output is disabled by default but this can be changed by using the Bluetooth Low Energy software stack from
Renesas.
This signal can also be used as the external main system clock for the MCU by connecting it to the EXCLK pin.
If this is the case, this pin must be connected to the EXCLK pin on the user board.
(2) EXSLK_RF
This is the input pin for the RF slow clock (32.768 kHz) if an external clock is used with the RF transceiver.
When this pin is used for an externally input clock signal (square wave) instead of using the on-chip oscillator, a
32.768-kHz input to this pin is required.
In this case, the Bluetooth low Energy software stack from Renesas sets up sub-clock output (32.768 kHz) through
the PCLBUZ0 pin to provide a square wave for input to EXSLK_RF. Accordingly, this pin and the PCLBUZ0 pin
must be connected, and the XT1 and XT2 pins must be connected to a 32.768-kHz crystal resonator on the user
board.
(3) RFCTLEN
This is an enable input pin for controlling the RF unit. The unit is enabled when the signal on the pin is at the high
level and disabled when the signal is at the low level, in which case the power supply to the RF internal circuit is
cut off.
Pin P130 of the MCU makes a transition to the high level on release from the reset state (changes from low to
high), so connect this pin with P130 on the user board.
(4) TXSELH_RF, TXSELL_RF
TXSELL_RF pin outputs low level from starting a packet transmission to starting the next receiving. It is Hi-Z in
DEEP_SLEEP mode, and outputs high level in the other period. Connect a pull-down resister equal or over 500 kΩ
to TXSELL_RF pin to set low level in DEEP_SLEEP mode.
(5) XTAL1_RF, XTAL2_RF
These pins are connected to a crystal resonator, which provides the base clock signal for the RF transceiver.
Connect a 32-MHz crystal resonator to these pins.
(6) GPIO0, GPIO1, GPIO2, GPIO3
These pins serve as a 4-bit input/output port.
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
CHAPTER 15 RF TRANSCEIVER
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