LPC1769 Pin Usage 1.5

This page documents the pin assignments for the LPC1769 microcontroller on Smoothieboard version 1.5.

It includes comparisons with version 1.0, as well as Edison and FPGA pin configurations.

Smoothieboard 1.0 vs 1.5

ARM Pin mBed Pin LPCXpresso Pin Smoothieboard 1.0 Smoothieboard 1.5 (Proposed) Comment
P0.0 P9 9 i2c1 sda i2c1 sda All: Internal I2C bus. Used for digipots and port expander.
P0.1 P10 10 i2c1 scl i2c1 scl All: Internal I2C bus. Used for digipots and port expander.
P0.2 USBTX 21 uart0 txd uart0 txd All: Used for ISP programming of the bootloader and for debugging.
P0.3 USBRX 22 uart0 rxd uart0 rxd All: Used for ISP programming of the bootloader and for debugging.
P0.4 P30 38 alpha_en_pin spare 1.5: recommended for encoder
Note: also is rs485 rd2
P0.5 P29 39 alpha_dir_pin spare 1.5: recommended for encoder
Note: also is rs485 td2
P0.6 P8 8 spi1 ssel spi1 ssel All: sdcard
P0.7 P7 7 spi1 sck spi1 sck All: sdcard
P0.8 P6 6 spi1 miso spi1 miso All: sdcard
P0.9 P5 5 spi1 mosi spi1 mosi All: sdcard
P0.10 P28 40 beta_en_pin spare
uart1 txd		 1.5: connected to edison uart1 rxd
Note: also i2c2 sda
P0.11 P27 41 beta_dir_pin spare
uart1 rxd		 1.5: connected to edison uart1 txd
Note: also i2c2 scl
… … … … … …
Note: The italicized pins are hardcoded and would need to be changed in the source code (P0.2, P0.3, P0.6 - P0.9, P0.29, P0.30, P2.9, P2.10). The rest are soft configurable in config. v1.5 Changes: The blue tagged pins have had their function changed for Smoothieboard v1.5

Edison Pin Usage

Chip Pin Module Pin Breakout Pin Arduino Pin Smoothieboard 1.5 Comment
GP109 55 J17.11   spi5 sck  
GP110 53 J18.10   spi5 ssel a  
GP111 51 J17.10   spi5 ssel b  
… … … … … …

FPGA Pin Usage

FPGA Pin Papilio Pin (One/Pro/Duo) Zpuino Pin Smoothieboard 1.5 Comment
B1.40P BH3 P62 mcu clkout  
B1.40N osc in - osc in  
B2.1P     spi0 sck main fpga spi slave port
… … … … …

Summary

Version 1.5 introduces several changes and optimizations compared to version 1.0.

New Functions in v1.5

The following new functions are available in version 1.5:

  • DAC (Digital-to-Analog Converter)
  • 5V PWM output
  • Edison UART interface
  • 2 servo outputs
  • Optional RS485 (not populated by default, pins free)

Pin Allocation Details

The pin allocation for version 1.5 uses advanced techniques to maximize available functionality:

  • The 5 enable pins will go on an 8-pin I2C IO expander (PCA9554B)
  • MS1, MS2, and RESET/SLEEP stepper pins will have pull-ups to expander pins
  • Expander pins unassigned: 0
  • MCU pins spared without FPGA: 2
  • MCU pins spared without Edison: 2
  • MCU pins unassigned: 0
  • Functions unassigned: 0

Display Support

For RRD display support, it is recommended that:

  • RS485 pins be used for encoder
  • Two FPGA pins be used for buttons

Compatibility Notes

Compatibility: This configuration currently appears to be 1 pin short of full backwards compatibility with v1.0. Balance: 0 MCU pins remaining.