3.1 Configuration.........................................................................................................................................................6
3.2 Run program..........................................................................................................................................................7
3.3 Text editor.............................................................................................................................................................8
3.4 File manager........................................................................................................................................................13
3.5 Command line.....................................................................................................................................................15
3.6 Hardware test......................................................................................................................................................17
3.7 Factory Reset.......................................................................................................................................................18
3.8 Update F/W (Firmware).......................................................................................................................................18
4.1 QDOS BASIC programs.........................................................................................................................................22
4.2 Variables..............................................................................................................................................................24
4.3 Tags in strings......................................................................................................................................................25
4.4 Operators............................................................................................................................................................27
4.5 LET statement (assignment)................................................................................................................................28
4.6 Expressions..........................................................................................................................................................28
4.7 Functions.............................................................................................................................................................28
4.7.1 IN function....................................................................................................................................................28
4.7.2 INA function..................................................................................................................................................29
4.7.3 RAND function..............................................................................................................................................29
4.7.4 VAL function.................................................................................................................................................30
4.7.5 INSTR function..............................................................................................................................................31
4.7.6 LEN function.................................................................................................................................................31
4.7.7 I2CR function and I2CR16 functions..............................................................................................................32
4.7.8 FILEEOF function...........................................................................................................................................32
4.8.1 FOR..NEXT loop structures............................................................................................................................33
4.8.2 IF..ELSE..ENDIF structures.............................................................................................................................34
4.8.3 GOTO............................................................................................................................................................35
4.8.4 Subroutines: GOSUB and RETURN................................................................................................................35
4.8.5 END...............................................................................................................................................................36
4.8.6 RUN statement.............................................................................................................................................37
4.9.1 PRINT statement...........................................................................................................................................37
4.9.2 DELAY statement..........................................................................................................................................38
4.9.3 SLEEP statement...........................................................................................................................................38
4.9.4 GPS statement..............................................................................................................................................39
4.9.5 Transmit statements: CW, HELL, JT9, JT65, WSPR, TELE...............................................................................40
4.9.6 OUT statement.............................................................................................................................................44
4.9.7 I2CW, I2CW16 statements............................................................................................................................45
4.9.8 File handling statements: FILE, FILEWR, FILERD, FILEDEL.............................................................................46
FILEWR statement.................................................................................................................................................47
FILERD statement..................................................................................................................................................47
FILEDEL statement.................................................................................................................................................48
5. QRP Labs tracking......................................................................................................................................................50
6. Resources.................................................................................................................................................................. 55
7. Document Revision History.......................................................................................................................................55
U4B operating manual Rev 1.00
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