Christian wrote:"self made" SD card logger
My effort on the development of an I2C_SDCard has resulted as follows:
QuadBow wrote: I am still struggling since the sd-lib does not seem to be compatible with the twi code
Probably, this issue is related to a RAM overflow causing restarts.
So, it is not possible to integrate the SD-card to the existing I2C-GPS without reducing many features of I2C-GPS.
Furthermore, SD-card access requires a lot of time (12ms for"Hello world !"). Therefore, an integration into an existing flight controller is not feasible. The issue is that the SPI-library waits for the completion of the transfer without using interrupts. Thus, the flight controller waits a long time delaying the cycle loop too much and risking an unstable operation.
byte SPIClass::transfer(byte _data) {
SPDR = _data;
while (!(SPSR & _BV(SPIF)));
...}
One possibility would be rewriting the SPI-lib in a more sophisticated way... smart programmers are welcome
My approach is to use another promini for the implementation of the I2C_SDCard. I am implementing following features:
- i2c-interface compatible with fast mode (400,000 baud)
- variables: voltage1, voltage2, current, power, rotations_per_second. temperature1, temperature2, pitch, roll, yaw, capacity_battery, energy_battery
- gps-vars: fix2d, fix3d, num_sats, lon, lat, alt, dist_to_home, ground_speed, ground_course (no nav variables)
- optional: min-, mid-, and max-values (not recommended for high speed applications like flight controllers)
- commands: sd_init, sd_start, sd_restart, sd_stop, sd_final, set_sd_rate, sd_send, sd_new_data
- flexible recording time above 100ms
- sleep instruction for power saving between records
- future extention: lcd integration (if enough flash and Ram remains...)
