17-11-2019, 09:23 PM
The software to unravel the 1170 bps serial data from the TDA7330 is simple. More complicated to drive the LCD panel if you don't have a library.
Right now I'm not sure where that is.
Here is the 7040 on its own for valve tuner.
Here is a €4 FM Tx PCB (bought locally) showing where RDS is fed in via a suitable resistor / capacitor from a PIC based encoder.
The pins of the IC are labelled. Also the channel / frequency selection switch and unused lines to select other channels. This IC also does channels in the Japan 76 to 90+ band.
The more common CE marked FM TX with an LCD and up/down arrows does the entire FM band, but the FM TX IC is controlled by the separate CPU via I2C that manages buttons and screen. Those can be got for about €12. There is no added quality with more expensive models. Also fed from Satellite, 256K MP3 or CD the quality of the cheapest ones is better than most local FM who have bad Optimod settings.
Some models only have space for one cell. Yet the IC is recommended for 2.75V to 3.5V! Better ones have two cells and 3.3V regulators. The ones with an auxiliary USB out (charge) need 8V to 9V on the power jack. No heatsink, so 12V in and using the USB charge is optimistic!
Right now I'm not sure where that is.
Here is the 7040 on its own for valve tuner.
Here is a €4 FM Tx PCB (bought locally) showing where RDS is fed in via a suitable resistor / capacitor from a PIC based encoder.
The pins of the IC are labelled. Also the channel / frequency selection switch and unused lines to select other channels. This IC also does channels in the Japan 76 to 90+ band.
The more common CE marked FM TX with an LCD and up/down arrows does the entire FM band, but the FM TX IC is controlled by the separate CPU via I2C that manages buttons and screen. Those can be got for about €12. There is no added quality with more expensive models. Also fed from Satellite, 256K MP3 or CD the quality of the cheapest ones is better than most local FM who have bad Optimod settings.
Some models only have space for one cell. Yet the IC is recommended for 2.75V to 3.5V! Better ones have two cells and 3.3V regulators. The ones with an auxiliary USB out (charge) need 8V to 9V on the power jack. No heatsink, so 12V in and using the USB charge is optimistic!
