-#define MB_HOLD_REGS_BASE 1000
-#define MB_N_HOLD_REGS 60
-#define MB_N_HOLD_REGS_EEPROM 20
+#define MB_HOLD_REGS_BASE 0 // first register
+#define MB_N_HOLD_REGS 80 // total # of registers
+#define MB_N_HOLD_REGS_EEPROM 20 // the first N registers eeprom-backed