text: #ifndef CDCACM_H
  #define CDCACM_H
  
  #include "usb/epc_usb.h"
  
  // callbacks for esb_config
  int esb_cdc_init(struct esb_config* self);
  int esb_cdc_configure(struct esb_config* self);
  int esb_cdc_deconfigure(struct esb_config* self);
  
  int cdcacm_num_read_avail(void);
  uint8_t cdcacm_read(void);
  void cdcacm_write(uint8_t *data, int len);
  
  #endif
  