EVB7122
27 to 930MHz Transceiver
Evaluation Board Description
Due to the static CMOS design, the SCI consumes virtually no current and it can be programmed in active
as well as in standby mode.
If the transceiver is set from standby mode to any of the active modes (idle, receive, transmit), the SCI
settings remain the same as previously set in one of the active modes, unless new settings are done on the
SCI while entering into an active mode.
Invalid
data
SDTA
Invalid
data
MSB
bit 23
bit 22
bit 1
LSB
bit 0
SCLK
t
CS
t
CH
t
CWL
t
CWH
SDEN
t
ES
t
EW
t
EH
Fig. 3:
Serial Data Input Timing
3
Register Description
As shown in the previous section there are four control words which stipulate the operation of the whole chip.
In Stand-alone User Mode SUM the intrinsic default values with respect to the applied levels at pins FS0 and
FS1 lay down the configuration of the transceiver. In Programmable User Mode (PUM) the register settings
can be changed via 3-wire interface SCI. The default settings which vary with the desired operating
frequency depend on the voltage levels at the frequency selection pins FS0 and FS1 before entering the
PUM. Table 5.1.1 shows the default register settings of different frequency selections. It should be noted that
the channel frequency listed below will be achieved with a crystal frequency of 7.1505 MHz. The following
table depicts an overview of the register configuration of the TH7122.
39012 07122 02
Rev. 005
Page 7 of 24
EVB Description
June/07
MELEXIS [ Melexis Microelectronic Systems ]
