XE1203 ETC1 [List of Unclassifed Manufacturers], XE1203 Datasheet - Page 14

• Manufacturer Part Number: XE1203
• Description: Low-Power, integrated UHF transceiver
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

Saout_rssi is internally generated signal during a read sequence of DATAOUT_RSSI register and used for
updating Dataout_RSSI register. The next figure shows the timing diagram of the saout_rssi generation.
The maximum frequency of SCK during the read operation of the RSSI value is 100 KHz.
4.1.10 Frequency Error Indicator - FEI
This function provides information about the frequency error of the local oscillator compared with the input carrier
frequency and can be used to implement AFC. The condition on the modulation index for proper behaviour of the
FEI function is:
where f is the frequency deviation and BR is the bit rate.
IMPORTANT NOTE
The time diagram of an FEI measurement is given in the next figure. When the FEI block has been woken up and
is ready, and as long as the block is kept on, the frequency error is measured and the current result of the
measurement is loaded in the register “Dataout_MSB_fei” and “Dataout_LSB_fei ‘’ each time the
“Dataout_LSB_fei ‘’ register is read. TS_FEI is the time required for the first evaluation to be completed after the
block has been started up and its value is given in section 3.2. Since the contents of the configuration register is
validated at the rising edge of the enable signal “en”, the FEI block is actually started up at this time.
14
EN
SO
SI
SCK
saout_rssi
HZ
2
BR
f
, 2
A4
A3
A2
Figure 7. Generation of saout_rssi
A1
A0
D7
D6
D5
D4
D3
D2
D1
Data Sheet
XE1203
D0
D0308-214
HZ