Si4020
Push-button 1:
00000080
00000090
000000A0
000000B0
000000C0
000000D0
000000E0
000000F0
88
55
55
55
55
55
55
00
72
55
55
55
55
55
55
00
A6
55
55
55
55
55
55
00
10
55
55
55
55
55
55
00
C6
55
55
55
55
55
55
00
60
55
55
55
55
55
55
00
55
55
55
55
55
55
C4
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
55
55
55
55
55
55
00
00
Short Explanation:
Address
80–81
82–83
84–85
86–E5
E6–E7
Command
Parameter
872
Related Control Command
Configuration Control
Frequency
Remarks
8
A
433MHz band, Xtal CL=12pF fdev=90kHz
fc=(43+1552/4000)*10MHz
Transmit the next 96 bytes
Data
610
C6
60
Data Transmit
60x55
00
C4
Sleep
Power down, go to address 80 (see note)
Note:
• This routine is repeatedly executed while PB1 is pressed, because continuous execution was selected at POR (CA1E code issued in the
power-on reset section before).
RX-TX ALIGNMENT PROCEDURES
RX-TX frequency offset can be caused only by the differences in the actual reference frequency. To minimize these errors it is
suggested to use the same crystal type and the same PCB layout for the crystal placement on the RX and TX PCBs.
To verify the possible RX-TX offset it is suggested to measure the CLK output of both chips with a high level of accuracy. Do not
measure the output at the XTL pin since the measurement process itself will change the reference frequency. Since the carrier
frequencies are derived from the reference frequency, having identical reference frequencies and nominal frequency settings at the
TX and RX side there should be no offset if the CLK signals have identical frequencies.
It is possible to monitor the actual RX-TX offset using the AFC status report included in the status byte of the receiver. By reading out
the status byte from the receiver, the actual measured offset frequency will be reported. In order to get accurate values the AFC has
to be disabled during the read by clearing the "en" bit in the AFC Control Command (bit 0).
22
SILICON [ SILICON ]
