Hello everyone,
I’m designing a PCB for a rocket payload and came across this forum while researching the RESET pin usage. It answered some questions but left me with a few more — I’d really appreciate your input, since I need this L86-M33 to run at maximum stability and performance.
VCC decoupling: I’m feeding 3.3V into VCC with a 100µF tantalum, 10µF, and 100nF placed in parallel on that rail. Is there any additional capacitor you’d recommend adding here for maximum stability?
V_BACKP: I’ve added a 4.7µF and 100nF in parallel on this line as well. Same question — any extra capacitor or component you’d suggest?
Configuration software: I read that around 2022 there was a configuration tool for the L86. If we plan to use the module at the standard 9600 baud rate, is running this tool necessary? Would updating the firmware/config improve the stability of the L86 modules we already have?
1PPS LED: Is it safe to drive a yellow LED off the 1PPS pin through a 330Ω resistor?
RESET pin: We’re using a tactile button for reset. Various AI tools have suggested a 10K pull-up to 3.3V before the button, with a 1–2.2µF capacitor in parallel on the same line, and connecting the button’s other side directly to GND. However, I’ve also seen other approaches (like pull-down configurations) mentioned elsewhere. What would you recommend?
TX/RX level shifting: We’re getting 5V TX out of an Arduino Nano Every into the L86’s RX pin, which needs level shifting. Instead of using a level-shifter IC like the TXS0108, I’m using a resistor divider (4.7k/6.2k) to bring it down to about 2.8V, plus a 1k series resistor on the L86’s RX line. Does this approach look sound for the L86’s TX pin as well?
Sorry for the long list of questions — I just really want to get this module running at its best in terms of both performance and stability.
Thanks in advance