I can't seem to make my radio module work right when I convert from the cheap transistor equivalent of the circuit to the recommended MAX232 version.
This is the max232 circuit I made.
The part on the top-right is the same circuit I used for the cheap transistor version
I also tried removing the 10K pull-up resistors (except for the one next to the jumper) and still no luck. The capacitors I used due to availability are 4.7uF each and the capacitors next to the regulators are 100uF each. Regulator at the top is LM1117 (5V to 3V regulator).
When I measured the output transmit pin voltage (that module connects to) and tried sending data to the unit, the voltage changes by only 0.01. When I measured pins 7 and 8, the voltage did change a lot which suggests to me things are working from the PC side.
Voltage changed by about 1 when I measured pins 9 and 10.
I also measured pins 2 and 6 and got about -7v and 7v
I made sure I had no short circuits anywhere.
I attached my PCB layout with all the components included and the grid is 0.635mm
and for reference, this is my older schematic for the adapter that did work for small data but not for large streams (especially of the same)
and its PCB:
What could I be doing wrong?
This is the max232 circuit I made.
The part on the top-right is the same circuit I used for the cheap transistor version
I also tried removing the 10K pull-up resistors (except for the one next to the jumper) and still no luck. The capacitors I used due to availability are 4.7uF each and the capacitors next to the regulators are 100uF each. Regulator at the top is LM1117 (5V to 3V regulator).
When I measured the output transmit pin voltage (that module connects to) and tried sending data to the unit, the voltage changes by only 0.01. When I measured pins 7 and 8, the voltage did change a lot which suggests to me things are working from the PC side.
Voltage changed by about 1 when I measured pins 9 and 10.
I also measured pins 2 and 6 and got about -7v and 7v
I made sure I had no short circuits anywhere.
I attached my PCB layout with all the components included and the grid is 0.635mm
and for reference, this is my older schematic for the adapter that did work for small data but not for large streams (especially of the same)
What could I be doing wrong?