AN201
Rev 1.5 | 31/91
www.cmostek.com
2.10 Pass-through Tx Mode (Advanced Configuration Mode)
2.10.1 Power-up initialization
1.
Upon chip power-up, it initializes ports and wait for 20 ms for stabilization.
2.
Control RFCTRL = 1.
3.
Configure PC3/CSB, PC2/SCLK and PC0/RFDIN as high resistance input. Configure PC1/SDIO as output 0.
4.
After initialization, the chip can enter low power based sleep state or perform other processing.
2.10.2 Tx Process
To implement the pass-through transmission in configuration mode, users need to follow the process below.
1.
Set PC0/RFDIN to 0 output.
2.
Control RFCTRL = 0. Enable the SPI interface of RF part. Send the command soft_rst and wait for 20 ms for stabilization.
3.
Set the register 0x34<3> to 1 and confirm the modification succeeds.
4.
Send the command go_stby through SPI and confirm RF is in the standby state (it is recommended to wait for 2 ms after
sending the command).
5.
Configure the related registers according to user requirements (configuration range is 0x00~0x03).
6.
Set the register 0x34<5> to 0, and then set the register 0x2A<1:0> to 0b01.
7.
Send the command go_tx through SPI, and start the chip transmission according to above configurations (it is
recommended to wait for 1 ms after sending the command).
8.
Control PC0/RFDIN to transmit the required data stream.
9.
After transmission completes, keep PC0/RFDIN to output 0.
10. Set the register 0x02<6:0> to 0 and set the register 0x4E<7> to 1.
11. Set the register 0x34<3> to 0 and confirm the modification succeeds.
12. Send the command go_sleep through SPI and enter sleep state.
13. Set the MCU pin that controls the RFCTRL to high resistance input. Switch PC3/CSB, PC2/SCLK and PC0/RFDIN to high
resistance input (internal pull-up). Switch PC1/SDIO to output 0. Then the MCU will also enter the sleep mode, namely the
whole device will enter the low power state.
Notes
1.
In the 5
th
step, it only needs to configure 0x00 ~ 0x03 to adjust Tx frequency and Tx power. Other register configurations can
be ignored.
2.
When the transmission is started up again, execute the Tx process once again.
3.
In step 3, 6, 1, 11, users need to use
read-modify-write
method to avoid modifying the value of other bits by mistake.
2.10.3 Related Register
