5 * open a log file on sd card.
7 * The format of the filename is "log%.4d". The choosen integer is the
8 * first file that doesn't exist on the sd card, starting from 0.
11 * 0 on success, negative value on error
13 int8_t sd_log_open(void);
16 * Write a buffer in the log file
18 * This function fails (return -1)if the log file was not opened.
21 * number of written bytes on success, negative value en error
23 intptr_t sd_log_write(const void *buffer, uintptr_t buffer_len);
26 * return true if log file was properly opened
28 uint8_t sd_log_enabled(void);