AT86RF230_09 ATMEL [ATMEL Corporation], AT86RF230_09 Datasheet - Page 68

• Manufacturer Part Number: AT86RF230_09
• Description: Low Power 2.4 GHz Transceiver for ZigBee, IEEE 802.15.4, 6LoWPAN, RF4CE and ISM
• Manufacturer: ATMEL [ATMEL Corporation]

9.6.3 External Reference Frequency Setup
9.6.4 Master Clock Signal Output (CLKM)
68
AT86RF230
Figure 9-4. Simplified XOSC Schematic with External Components
When using an external reference frequency, the signal needs to be connected to pin
XTAL1 as indicated in Figure 9-5 and the register XTAL_MODE of register 0x12
(XOSC_CTRL) need to be set to the external oscillator mode. The oscillation peak-to-
peak amplitude shall be 400 mV, but not larger than 500 mV.
Figure 9-5. Setup for Using an External Frequency Reference
The generated reference clock signal can be fed to a microcontroller using pin 17
(CLKM). The internal 16 MHz raw clock can be divided by an internal prescaler. Thus,
clock frequencies of 16 MHz, 8 MHz, 4 MHz, 2 MHz or 1 MHz can be supplied by
pin CLKM.
The CLKM frequency and pin driver strength is configurable using register
0x03 (TRX_CTRL_0). There are two possibilities to change the CLKM frequency. If
CLKM_SHA_SEL = 0, changing the register bits CLKM_CTRL (register 0x03,
TRX_CTRL_0)
(CLKM_SHA_SEL = 1) the new clock rate is supplied when leaving the SLEEP state
the next time.
XTAL_TRIM[3:0]
XTAL2
C
TRIM
XTAL2
immediately
C
PAR
EVDD
CX
16MHz
affects
XTAL1
16 MHz
AT86RF230
the
PCB
XTAL1
CX
CLKM
AT86RF230
C
XTAL_TRIM[3:0]
TRIM
C
PAR
PCB
clock
5131E-MCU Wireless-02/09
rate.
Otherwise