AN201
Rev 1.5 | 9/91
www.cmostek.com
5.
In this mode, the data transmitting pin is PC1 (SDIO), which is set to 0 in the low power state (the normal state). When data
transmitting is needed, it triggers on the rising edge to enter data transmitting state. After transmitting, PC1 is set to 0 and
lasts for more than 20 ms (T
OFF
time), and RF exits from the Tx mode automatically to enter the low power state.
6.
For this mode, in low power state, PC1/SDIO is set 0 to output and PC2/SCLK, PC3/CSB, and PC0/RFDIN are set to high
resistance input.
2.3 Advanced Configuration Mode
To achieve higher performance and more functions such as the target operating frequency of 868MHz and chip automatic packet
transmitting in transmission process, users need to use the advanced configuration mode with supports of the following features.
Support more frequency multiplication factors to cover a frequency range of 240 ~ 960 MHz.
By filling the FIFO and transmitting the message automatically (repeatedly, multiple times and periodically), it can
release the MCU to do more work (In the pass-through mode, this process will take up MCU resource).
Support more accurate Tx rates with the accuracy determined by crystal, which is excellent in accuracy (in the
pass-through mode, the speed is controlled by the MCU software, and the accuracy depends on the software and the
internal RC).
Support voltage detection function inside RF, which offers simple power supply voltage detection and analysis
judgment processing.
Dynamical Tx power adjustment according to the power supply voltage to save power and prolong battery life.
In this mode, the chip internal MCU can have the RF mode control by operating registers through the 3-wire SPI (PC3/CSB,
PC2/SCLK, PC1/SDIO) to fulfill the 2 Tx modes.
1.
Hardware packet Tx mode, which fills FIFO through SPI (see Section 2.9 for details)
The contents that need to be transmitted are filled into specified registers, which are automatically transmitted according t o the
speed, coding mode, number of packets and packet interval, etc.(the data package format and other relevant information are
detailed in Section 2.7).
2.
Pass-through Tx mode using PC0/RFDIN as data pin (see Section 2.10 for details)
That is, the 1-Pin Tx mode, the data stream is generated by the MCU and output through the specified pin to fulfill the most
elementary operating mode, namely
data pin in, antenna out
.
Notes:
1.
The 2 Tx modes mentioned above are all in the advanced configuration mode, namely configuring and operating the chip
through SPI.
2.
In the advanced configuration mode, it is required to control RFCTRL through other pins, therefore the RFCTRL pin cannot
be suspended.
3.
The pass-through mode in the advanced configuration mode is similar to the pass-through mode in simple operating mode,
namely they both control data transmitting through a data pin, however the data input sources are different. In simple
operating mode, the Tx input pin is PC1/SDIO, while in the advanced configuration mode, it is changed to PC0/RFDIN
because PC1/SDIO is used as the serial data line of SPI. With both using the register configuring method, the pass-through
mode in advanced configuration mode can support more frequency selection and power selection than that in the simple
operating mode.
