Hi,
I am configuring a test software to generate CW signals at channel 0, 19 and 39. Currently I'm using the nRF52840dk, later a custom board. The channel number is calculated according to f=2402+n*2 MHz so I expect for n=39 2480 MHz. For n=38, I measure the expected 2478 MHz.
For n=39 I get 2479.75 MHz Why is it 250 kHz off ? Is that normal ?
The software is based on the direct_test_mode example. I added the followng code:
uint16_t test_command_assemble(uint8_t cmd_code, uint8_t channel, int setupCode ) {
uint16_t returnValue=0;
if (cmd_code==LE_TEST_SETUP) {
//uint8_t setupCode = setupCode;
returnValue=returnValue+(LE_TEST_SETUP << 14) + (setupCode <<8) + channel; // use channel to code e.g. TX-Power
}
if (cmd_code==LE_TEST_END) {
returnValue=returnValue+(LE_TEST_END << 14);
}
if (cmd_code==LE_TRANSMITTER_TEST) {
returnValue=returnValue+(LE_TRANSMITTER_TEST << 14) + (channel << 8) + DTM_PKT_0XFF_OR_VS; // DTM_PKT_0X55;
}
return(returnValue);
}
and
uint16_t dtm_cmds[12];
dtm_cmds[0]=test_command_assemble(LE_TEST_SETUP,0,LE_TEST_SETUP_RESET); //
dtm_cmds[1]=test_command_assemble(LE_TEST_SETUP,0, LE_TEST_SETUP_TRANSMIT_POWER); // set tx-level to 0 dbm;
dtm_cmds[2]=test_command_assemble(LE_TRANSMITTER_TEST,39,0);// test channel n=39; f=2402+n*2 MHz, n=0..39 (BTLE)
dtm_cmds[3]=test_command_assemble(LE_TEST_END,0,0); // stop transmission or other testsand in the main loop I send the commands, with a 10s delay during the actual test.
dtm_cmd=dtm_cmds[cmd_counter++];
Best regards,
Moritz
