AN201
Rev 1.5 | 8/91
www.cmostek.com
2 RF Part Configuration and Control
Mechanism
2.1 Operating Mode
The built-in OOK Tx function of the CMT2189B supports 2 operating modes.
Simple operating mode: the default entry mode upon power-up, namely, the non-configuration mode, which supports the
pass-through Tx mode only.
Advanced configuration mode: it supports register configuration and operating state control through the SPI bus, which
supports both the FIFO and pass-through Tx mode.
Notes:
1.
The pass-through Tx input sources in the 2 operating modes are different. Please see more details in below Sections.
2.2 Simple Operating Mode
In the simple operating mode, the only peripheral required is a crystal oscillator. Upon power-up, the chip controls data
transmission through the internal PC1 (SDIO) to fulfill data transmission at the corresponding frequency. In this mode, the
frequency multiplier factor is fixed to 16.5, calculated based on the following formula.
314 MHz ≤ F
RF
≤ 480 MHz,
where FXTAL is the crystal frequency and FRF is the target frequency, and the frequency range is 314 MHz ~ 480MHz.
T
OFF
PC1/SDIO
STATE
PA _ OUT
SLEEP
CALS
PLL
TX
SLEEP
PA _ OUT
Figure 3. Tx Timing Diagram in the Simple operating Mode
Notes:
1.
This mode supports a rate range of 1 ~ 20 kbps.
2.
The maximum power output is fixed to +13 dBm. Users can reduce the Tx power by connecting a resistor to limit current
before the chock inductor if it is needed.
3.
The internal SPI bus does not need to send any control commands and only needs to hold PC<3:0> in a high resistance
input status (except PC1).
4.
The RFCTRL pin can be suspended in this mode.
