Table of Contents

LPC812 Node

Introduction

The LPC812 is a 32-bit ARM Cortex-M0+ chip which is cheap, easily available and relatively easy to solder with just a standard iron. It contains a bootloader and so can be programmed over serial. Onboard it has:

MK1 (v1.0)

This is a double sided board (LPC812 on front and RFM69 footprint on the back) with all the pins broken out, space for a diode and large capacitor and a prototyping area. It was designed to be a chance to try and create a solar powered capacitor node (though the capacitor was really too small to be helpful) and so doesn't have a regulator. This can be added easily taking advantage of the protoboard section.

Required Components

MK2 (v1.1)

Similar to MK1, smaller and slight reorganisation of pins - moved one SPI pin to allow access to ACMP which means that we can measure voltage using the comparator. Also removed diode and cap and instead added MCP1700 voltage regulator and caps. Ordered through dirtyPCB which meant that the protoboard section didn't come out as planned (just as vias). Also added JP1 header (VCC, Tx, Rx, GND) which makes it easy to add a GPS module.

Required Components

Erebus (v1.1)

New board design again with a LPC812 and RFM69, smaller PCB size and instead of standard voltage regulator the use of a DC/DC stepup convertor. The step up is set to output 3.3v and the board can boot from as low as 0.8V. Ordered PCBs from dirtypcb and have built up 1 board, found an error where I haven't connected the SHDN pin on the step up which needs to be pulled up to function.

Components

Headers

JP1

  1. GND
  2. VIN

JP2

  1. VCC
  2. PIO0_17 (UART1_RX)
  3. PIO0_13 (UART1_TX)
  4. NC
  5. PIO0_10
  6. GND

JP3

  1. Reset
  2. PIO0_12 (ISP)
  3. GND
  4. GND
  5. PIO0_4 (TX)
  6. PIO0_0 (RX)

Improvements

Compiling the Firmware

Flashing the LPC812