#include <bluefruit.h>

#define MAX_CENTRAL_LINKS 15  // Target 15+ connections

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10);

  // CRITICAL: Configure connection parameters BEFORE begin()
  // Reduce MTU to ~100 bytes (saves ~300 bytes per connection vs 247)
  // Reduce event length to 3 (3.75 ms, sufficient for notifications)
  // Minimal queues since HM-10 modules typically don't burst data
  
  uint16_t mtu = 100;           // Reduced from 247
  uint16_t event_len = 3;       // Reduced from default 6
  uint8_t hvn_qsize = 1;        // Reduced from 3
  uint8_t wrcmd_qsize = 1;      // Reduced from 3
  
  Bluefruit.configCentralConn(mtu, event_len, hvn_qsize, wrcmd_qsize);
  
  // Optional: Reduce attribute table if not using many services
  // Bluefruit.configAttrTableSize(0x800); // Default is 0x1000 on nRF52840
  
  // Optional: Limit 128-bit UUIDs to save RAM
  // Bluefruit.configUuid128Count(5); // Default is 10

  // Initialize with target connection count
  // Format: begin(peripheral_count, central_count)
  Bluefruit.begin(0, MAX_CENTRAL_LINKS);
  
  // ... rest of your central setup code
}

/* Default may be: ORIGIN = 0x20003200 */
/* You need to increase this to accommodate more connections */

MEMORY
{
  /* Flash sections omitted... */
  
  RAM (rwx) : ORIGIN = 0x20004180, LENGTH = 0x0003BE80  /* Increased base */
}