Rtc Clock (32.768 Khz); Figure 12: Write New Xtal Value; Table 6: Rtc Crystal Requirements - Renesas DA16200 H/W User Manual

UM-WI-006
DA16200 H/W Design Guide
a. Enter 'AT+XTALWR=<value>' command. <value> is desired value and seven-bits to write [h'1 ~
h'7f].
b. Click the Send button.
NOTE
If the register value is changed significantly, writing the value may not be possible. Change the
value within 10.
5. Check Tx frequency change on spectrum analyzer.
6. Repeat steps 4 and 5 to find the correct value.
Dialog highly recommend calibrating the RF XTAL on production line as the frequency tolerance of
Wi-Fi specification is within ±20 ppm. [2]describes how to adopt the calibration on mass production.
See section 5. XTAL Calibration on UM-WI-011.
In the DA16200 module (DA16200MOD), RF XTAL is calibrated. So, customer doesn't need to think
about the calibration.
2.5.2

RTC Clock (32.768 KHz)

The 32.768 kHz RTC clock source is necessary for the free-running counter in the RTC block. The
external clock is 32.768 kHz. Make sure that the load capacitance is tuned based on the board
parasitic so that the frequency tolerance is within ±250 ppm.
The recommended operating conditions are given in

Table 6: RTC Crystal Requirements

Parameter
Frequency
Frequency accuracy
Crystal ESR
User Manual
CFR0012

Figure 12: Write New XTAL Value

Condition
Initial + temp + aging
32.768 kHz, C1 = C2 = 9 pF
Revision 1.5
19 of 44
Table 6.
Min Typ
32.768
-250
NDA Confidential
Max Units
kHz
+250 ppm
Ω
90
11-Apr-2022
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