The ClearCore libraries are installed at:
C:\Users\<you>\AppData\Local\Arduino15\packages\ClearCore\hardware\sam\<version>\libraries

Modbus features:
     Function Codes 1, 2, 3, 4, 5, 15, 6, 16
     Single thread - polling interface, not time critical
     Fast - low cpu usage, up to 921600 baud
     supports RS232 and RS485 (incl multi-drop) w/auto-flow-control
     independent from register definition (user-supplied bounds check)
          assumes contiguous array of 16 bit regs, but user can 
          enforce bounds check per function code
     Supports 256 byte PDU/ADU
     Supports char/byte (multiples of 2), int16/32, uint16/32, 
      and float data types mapped to uint16 array[]
     Does not support broadcast to slave addr 0
     Server
          Efficient - app notified when data has been refreshed
          can only process one request at a time
          request executes in about 200us
          register layout described with simple C++ struct
     Client
          can only process one request at a time 
               i.e. send_req, wait_response, repeat
          but never blocks caller (polled, ~100us execution)
     1650 lines, 650 lines code + 1000 comment/blank

From Arduino Library Spec:
A hypothetical library named "Servo" that adheres to the specification follows:

Servo/
Servo/library.properties
Servo/keywords.txt
Servo/src/
Servo/src/Servo.h
Servo/src/Servo.cpp
Servo/src/ServoTimers.h
Servo/examples/
Servo/examples/Sweep/Sweep.ino
Servo/examples/Pot/Pot.ino
Servo/extras/
Servo/extras/Servo_Connectors.pdf  
