Si4021
19
9. Wake-Up Timer Command
bit     15     14     13     12     11     10
9
8
7
6
5
4
3
2
1
0
POR
1
1
1
r4
r3
r2
r1
r0     m7    m6    m5    m4    m3    m2    m1    m0
E000h
The wake-up time period can be calculated as:
T
wake-up
= M * 2
R
[ms] ,
where M is defined by the <m7 : m0> digital value and R is defined by the <r4 : r0> digital value.
The value of R should be in the range of 0 and 23. The maximum achievable wake-up time period can be up to 24 days.
Note:
?    For continual operation the et bit should be cleared and set at the end of every cycle.
Software reset: Sending FE00h command to the chip triggers software reset. For more details see the Reset modes section.
10. Data Transmit Command
In EEPROM operation mode:
bit     15     14     13     12     11     10
9
8
7
6
5
4
3
2
1
0
POR
1
1
0
0
0
1
1
0
n7     n6     n5     n4     n3     n2     n1     n0
- -
In microcontroller slave mode:
bit
7
6
5
4
3
2
1
0
1
1
0
0
0
1
1
0
This command indicates that the following bitstream coming in via the serial interface is to be transmitted. In EEPROM mode, the 8-bit value
N of bits <n7 : n0> contains the number of data bytes to follow.
Note:
?    This command is not needed if the transmitters power management bits (ex, es, ea) are fully controlled by the microcontroller and
TX data comes through the FSK pin.
?    If the crystal oscillator was formerly switched off (ex=0), the internal oscillator needs t
sx
time, to switch on. The actual value
depends on the type of quartz crystal used.
?    If the synthesizer was formerly switched off (es=0), the internal PLL needs t
sp
startup time. Valid data can be transmitted only when
the internal locking process is finished.
?    In EEPROM mode, before issuing the Data Transmit Command, the power amplifier must be enabled, with the ea or a0 bit in the
Power Management Command.
?    In EEPROM mode, when N bytes have been read and transmitted the controller continues reading the EEPROM and processing the
data as control commands. This process stops after Sleep Command has been read from the EEPROM.