sticilface

Guide to PROGMEM on ESP8266 and Arduino IDE

Intro

On low memory devices like the arduino and esp8266 you do not want strings to be stored in RAM. This occurs by default on these systems. Declare a string const char * xyz = "this is a string" and it will use up RAM.

The solution on these devices is to allow strings to be stored in read only memory, in Arduino this is the PROGMEM macro. Most of my experience is with the ESP8266 which is a 32bit micros controller. This device stores PROGMEM data in flash. The macro PROGMEM on ESP8266 is simply

#define PROGMEM   ICACHE_RODATA_ATTR

sbilly

Common ZeroTier Rules Engine question

• Non-servers can talk to servers, but not each other
• Kind of like Client Isolation on some WiFi controllers

Rules

# Allow only IPv4, IPv4 ARP, and IPv6 Ethernet frames. Typical default
drop
not ethertype ipv4
and not ethertype arp