fhunleth

RPi Zero 2 W, 32-bit, OTP 26

EStone test completed
**** CPU speed UNKNOWN MHz ****
**** Total time 17.605631 seconds ****
**** ESTONES = 38607 ****

    Title                            Millis        Estone       %    Loops

fhunleth

Add this to erlang.mk:

define ERLANG_BUILD_GPROF
        $(TARGET_MAKE_ENV) $(ERLANG_CONF_ENV) TARGET='riscv64-buildroot-linux-gnu' $(MAKE) -C $(@D)/erts/emulator gprof
endef

ERLANG_POST_BUILD_HOOKS += ERLANG_BUILD_GPROF

fhunleth

Putting the BBBW's eMMC into pSLC mode on Nerves

WARNING: I don't believe there's a way to undo this.

The BBBW has a 4 GB eMMC. For better reliability, I'm trying to put it into pSLC mode. Since the 4 GB eMMC is an MLC Flash with 2-bits per cell, converting it to pseudo-SLC mode (1-bit per cell) halves the total size.

Here's the original eMMC information:

fhunleth

ElixirConf Demo

Introduction

This is a simplified version Masatoshi Nishiguchi's bmp280.livemd notebook that's included in Nerves Livebook. Check out that notebook if you'd like to try this out yourself.

Setup

fhunleth

See the Elixir binary pattern docs

Goals

1. Consistency between code bases
2. Conciseness of patterns

Conventions for integer and float fields

1. All integers are specified with the fields in --- order

fhunleth

#!/bin/sh

#
# Upload new firmware to a target running nerves_firmware_ssh
#
# Usage:
#   upload.sh [destination IP] [Path to .fw file]
#
# If unspecifed, the destination is nerves.local and the .fw file is naively
# guessed

fhunleth

=============================================
  Extended CSD rev 1.8 (MMC 5.1)
=============================================

Card Supported Command sets [S_CMD_SET: 0x01]
HPI Features [HPI_FEATURE: 0x01]: implementation based on CMD13
Background operations support [BKOPS_SUPPORT: 0x01]
Max Packet Read Cmd [MAX_PACKED_READS: 0x3c]
Max Packet Write Cmd [MAX_PACKED_WRITES: 0x3c]
Data TAG support [DATA_TAG_SUPPORT: 0x01]

fhunleth

umask 0022 && make -C /home/fhunleth/nerves/nerves_system_br/buildroot-2020.05 O=/home/fhunleth/nerves/nerves_system_br/o/rpi0/. 
for p in https+https://github.com/erlang/otp/archive/OTP-23.0.2.tar.gz ; do \
	if test ! -e /home/fhunleth/dl/erlang/`basename $p` ; then \
		echo ">>> erlang 23.0.2 Downloading" ; \
		break ; \
	fi ; \
done
mkdir -p /home/fhunleth/dl/erlang
PATH="/home/fhunleth/nerves/nerves_system_br/o/rpi0/host/bin:/home/fhunleth/nerves/nerves_system_br/o/rpi0/host/sbin:/home/fhunleth/.asdf/shims:/home/fhunleth/.asdf/bin:/home/fhunleth/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin" BR2_DL_DIR="/home/fhunleth/nerves/nerves_system_br/buildroot-2020.05/dl" BUILD_DIR=/home/fhunleth/nerves/nerves_system_br/o/rpi0/build O=/home/fhunleth/nerves/nerves_system_br/o/rpi0 flock /home/fhunleth/dl/erlang/ support/download/dl-wrapper -c '23.0.2' -d '/home/fhunleth/dl/erlang' -D '/home/fhunleth/dl' -f 'OTP-23.0.2.tar.gz' -H 'package/erlang//erlang.hash' -n 'erlang-23.0.2' -N 'er

fhunleth

UPDATE: THIS WAS WRITTEN BEFORE BlueHeron EXISTED

This is a braindump of my progress over the weekend to look into Bluetooth support on Nerves. While Bluetooth has a lot of specs, supporting a subset of BLE that makes it easy for Nerves devices to communicate with cell phones and back would be generally useful.

There are two options for BLE support on Nerves:

1. Make a custom Nerves system that uses bluez
2. Use Harald

fhunleth

defmodule Barometer do
  alias ElixirALE.I2C

  @sealevel_pa 101325

  @doc """
  Put the BMP280 in normal mode and sample the temperature and
  pressure sensor at ultra high resolution.
  """
  def enable() do