V tomto článku se podíváme, jak nastavit na PicoW bezestavově IPv6 adresu a používat UDP protokol k posílání dat na server. PicoW bude sloužit jako bezdrátová sonda měření teploty. Data naměřené teploty budeme sbírat na serveru.
Předpoklady
Máme k dispozici Wifi Access Point, který umí přidělovat IPv6 adresy bezestavovou konfigurací (IPv6 Stateless Address Auto-configuration (SLAAC)).
Program
main.c
#include <stdio.h>
#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"
#include "lwip/pbuf.h"
#include "lwip/udp.h"
#include "lwip/ip6_addr.h"
#include "hardware/adc.h"
#include "setupWifi.h"
#define KAM_POSLAT "2a12:b7c0:3:1ff::1aa1"
int connect()
{
char ssid[] = "chorche";
char pass[] = "xxxxxxxxxxxx";
uint32_t country = CYW43_COUNTRY_CZECH_REPUBLIC;
uint32_t auth = CYW43_AUTH_WPA2_MIXED_PSK;
return setup(country, ssid, pass, auth, "PicoW6-teplota", NULL, NULL);
}
int main()
{
int connection_status = 0;
const float conversion_factor = 3.319f / ( 1 << 12 );
uint16_t result;
float teplota;
float adc;
stdio_init_all();
// nastavení a výběr interního čidla
adc_init();
adc_set_temp_sensor_enabled(true);
adc_select_input(4);
// nastavení měniče na malý šum
gpio_set_function(23, GPIO_FUNC_SIO);
gpio_set_dir( 23, true );
gpio_put( 23, 1 );
sleep_ms(10000); // pro připojení minicomu
printf("\nMěření teploty a posílání na UDP server v 0.1-6.\n");
do {
printf("Připojuji se k AP.\n");
connection_status = connect();
} while ( connection_status != CYW43_LINK_UP);
printf("Připojeno.\n");
printf("Linková IPv6 adresa: %s\n", ip6addr_ntoa(netif_ip6_addr(netif_default,0)));
printf("Globální IPv6 adresa: %s\n", ip6addr_ntoa(netif_ip6_addr(netif_default,1)));
printf("Host Name: %s\n", netif_get_hostname(netif_default));
struct udp_pcb *pcb = udp_new_ip_type(6);
char moje_ip_buf[64];
sprintf(moje_ip_buf,"%s", ip6addr_ntoa(netif_ip6_addr(netif_default,1)));
ip6_addr_t moje_ip;
ip6addr_aton(moje_ip_buf, &moje_ip);
IP_SET_TYPE_VAL(&moje_ip, IPADDR_TYPE_V6);
udp_bind(pcb, &moje_ip, 4848);
ip6_addr_t ip_kam;
ip6addr_aton(KAM_POSLAT, &ip_kam);
IP_SET_TYPE_VAL(&ip_kam, IPADDR_TYPE_V6);
printf("IPv6 adresa na posílání: %s\n", ip6addr_ntoa(&ip_kam));
udp_connect(pcb, &ip_kam, 4848);
static char message[256];
while( true ){
result = adc_read();
adc = result * conversion_factor;
// teplota bez korekce
teplota = 27.0f - (adc - 0.706f) / 0.001721f;
memset(message,'\0',256);
sprintf(message, "Teplota: %5.1f ˚C\n", teplota);
struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, 256, PBUF_RAM);
snprintf(p->payload, strlen(message)+1, "%s", message);
err_t er = udp_send(pcb,p);
pbuf_free(p);
printf("Poslal jsem: 'Teplota: %5.1f ˚C', %s\r", teplota, er==0?"OK":"chyba");
sleep_ms(1000);
}
return 0;
}setupWifi.h
/* Nastavení Wifi karty */
int setup(uint32_t country, const char *ssid, const char *pass,
uint32_t auth, const char *hostname, ip_addr_t *iplocal,
ip_addr_t *ipglobal)
{
if (cyw43_arch_init_with_country(country))
{
return 1;
}
cyw43_arch_enable_sta_mode();
if (hostname != NULL)
{
netif_set_hostname(netif_default, hostname);
}
if (cyw43_arch_wifi_connect_async(ssid, pass, auth))
{
return 2;
}
int flashrate = 1000;
int status = CYW43_LINK_UP + 1;
while (status >= 0 && status != CYW43_LINK_UP)
{
int new_status = cyw43_tcpip_link_status(&cyw43_state, CYW43_ITF_STA);
if (new_status != status)
{
status = new_status;
flashrate = flashrate / (status + 1);
printf("Stav připojování: %d %d\n", status, flashrate);
}
cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
sleep_ms(flashrate);
cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
sleep_ms(flashrate);
}
if (status < 0)
{
cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
}
else
{
cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
if (iplocal != NULL)
{
//iplocal = (ip_addr_t) netif_ip6_addr(netif_default,0);
}
if (ipglobal != NULL)
{
//ipglobal = (ip_addr_t) (netif_default,1);
}
}
return status;
}lwipopts.h
#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
#define _LWIPOPTS_EXAMPLE_COMMONH_H
// Common settings used in most of the pico_w examples
// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html for details)
// allow override in some examples
#ifndef NO_SYS
#define NO_SYS 1
#endif
// allow override in some examples
#ifndef LWIP_SOCKET
#define LWIP_SOCKET 0
#endif
#if PICO_CYW43_ARCH_POLL
#define MEM_LIBC_MALLOC 1
#else
// MEM_LIBC_MALLOC is incompatible with non polling versions
#define MEM_LIBC_MALLOC 0
#endif
#define MEM_ALIGNMENT 4
#define MEM_SIZE 4000
#define MEMP_NUM_TCP_SEG 32
#define MEMP_NUM_ARP_QUEUE 10
#define PBUF_POOL_SIZE 24
#define LWIP_ARP 1
#define LWIP_ETHERNET 1
#define LWIP_ICMP 1
#define LWIP_RAW 1
#define TCP_WND (8 * TCP_MSS)
#define TCP_MSS 1460
#define TCP_SND_BUF (8 * TCP_MSS)
#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
#define LWIP_NETIF_STATUS_CALLBACK 1
#define LWIP_NETIF_LINK_CALLBACK 1
#define LWIP_NETIF_HOSTNAME 1
#define LWIP_NETCONN 0
#define MEM_STATS 0
#define SYS_STATS 0
#define MEMP_STATS 0
#define LINK_STATS 0
// #define ETH_PAD_SIZE 2
#define LWIP_CHKSUM_ALGORITHM 3
#define LWIP_DHCP 0
#define LWIP_IPV4 0
#define LWIP_IPV6 1
#define LWIP_IPV6_AUTOCONFIG 1
#define LWIP_TCP 0
#define LWIP_UDP 1
#define LWIP_DNS 0
#define LWIP_TCP_KEEPALIVE 0
#define LWIP_NETIF_TX_SINGLE_PBUF 1
#define DHCP_DOES_ARP_CHECK 0
#define LWIP_DHCP_DOES_ACD_CHECK 0
#define LWIP_CHECKSUM_ON_COPY 1
#define LWIP_CHECKSUM_GEN_UDP 1
#define LWIP_IPV6_SCOPES 0
#ifndef NDEBUG
#define LWIP_DEBUG 1
#define LWIP_STATS 1
#define LWIP_STATS_DISPLAY 1
#endif
#define ETHARP_DEBUG LWIP_DBG_OFF
#define NETIF_DEBUG LWIP_DBG_OFF
#define PBUF_DEBUG LWIP_DBG_OFF
#define API_LIB_DEBUG LWIP_DBG_OFF
#define API_MSG_DEBUG LWIP_DBG_OFF
#define SOCKETS_DEBUG LWIP_DBG_OFF
#define ICMP_DEBUG LWIP_DBG_OFF
#define INET_DEBUG LWIP_DBG_OFF
#define IP_DEBUG LWIP_DBG_OFF
#define IP_REASS_DEBUG LWIP_DBG_OFF
#define RAW_DEBUG LWIP_DBG_OFF
#define MEM_DEBUG LWIP_DBG_OFF
#define MEMP_DEBUG LWIP_DBG_OFF
#define SYS_DEBUG LWIP_DBG_OFF
#define TCP_DEBUG LWIP_DBG_OFF
#define TCP_INPUT_DEBUG LWIP_DBG_OFF
#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
#define TCP_RTO_DEBUG LWIP_DBG_OFF
#define TCP_CWND_DEBUG LWIP_DBG_OFF
#define TCP_WND_DEBUG LWIP_DBG_OFF
#define TCP_FR_DEBUG LWIP_DBG_OFF
#define TCP_QLEN_DEBUG LWIP_DBG_OFF
#define TCP_RST_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_OFF
#define TCPIP_DEBUG LWIP_DBG_OFF
#define PPP_DEBUG LWIP_DBG_OFF
#define SLIP_DEBUG LWIP_DBG_OFF
#define DHCP_DEBUG LWIP_DBG_OFF
#endif /* __LWIPOPTS_H__ */CMakeLists.txt
cmake_minimum_required(VERSION 3.13)
set(PICO_BOARD pico_w)
set (CMAKE_C_STANDARD 11)
set (CMAKE_CXX_STANDARD 17)
include(pico_sdk_import.cmake)
project(PicoW_UDP C CXX ASM)
pico_sdk_init()
add_executable(main
main.c
)
target_include_directories(main PRIVATE ${CMAKE_CURRENT_LIST_DIR})
target_link_libraries( main
pico_stdlib
pico_cyw43_arch_lwip_threadsafe_background
hardware_adc
)
pico_enable_stdio_usb(main 1)
pico_enable_stdio_uart(main 0)
pico_add_extra_outputs(main)Jednoduchý server v Pythonu na zobrazení došlých dat (běží na serveru).
udp_server.py
import asyncio
class ClientDatagramProtocol(asyncio.DatagramProtocol):
def datagram_received(self, data, addr):
message = data.decode("utf8")
print("Received",message,"from", addr)
async def main():
loop = asyncio.get_running_loop()
transport, protocol = await loop.create_datagram_endpoint(
lambda: ClientDatagramProtocol(),
local_addr=('::', 4848))
await asyncio.sleep(100000)
transport.close()
asyncio.run(main())