Dusty API UART

Note

This section will refer to the companion/external processor (the UNO DuinoPro) as the MCU.

Abstract

The Dusty module (the Eterna) is connected to the MCU through the API UART and is solely used as a networking device. The Dusty module is in slave mode and none of the built in I/Os are accessible in this mode [2]

Key design decisions:

  1. The Dusty module is set to slave mode
  2. The Dusty module will use the API UART to I/F with the MCU
  3. The API UART is used with mode 4

API vs CLI

There are two interfaces to the Dusty (LTC5800-IPM) module [1]:

  1. The API UART is the principle network interface.
  2. The CLI UART is an additional interface for testing and debugging

Serial Modes

The fuse table for the LTC5800-IPM is normally developed as part of the board level design process. Either mode 2 or mode 4 may be used on the API port, at either baud rate. For modularly certified products such as the LTP5901-IPM, or the Starter Kit mote (DC9003A-B)

Mode I/F Baud Rate API CLI
0 2w; RX and TX 9600 No Yes
2 6w; All lines 9600 or 115.2k Yes No
4 4w; TX, RX, _CTSn, RTSn 9600 or 115.2k Yes No

Flow Control

  1. MCU-to-Dusty transfers are initiated by the MCU driving the UART_RX_RTSn line
  2. Dusty responds by asserting the UART_RX_CTSn

Power Consumption of the I/F

Both UART I/Fs (API and CLI) sense activity continuously, consuming virtually no power until data is transferred and automatically returning to their lowest power state after the conclusion of a transfer [1]

Mode 2 is said to be the more energy efficient mode