Added minimal HW support for onboard WiFi modem. (#287)

variants/challenger_2040_wifi/ChallengerWiFi.cpp

+/*
+    ESP8285 helper class for the Challenger RP2040 WiFi boards
+
+    Copyright (c) 2021 P. Oldberg <pontus@ilabs.se>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include <Arduino.h>
+#include <ChallengerWiFi.h>
+
+Challenger2040WiFiClass::Challenger2040WiFiClass() {
+  pinMode(PIN_ESP8285_RST, OUTPUT);
+  digitalWrite(PIN_ESP8285_RST, LOW);       // Hold ESP8285 in reset
+  pinMode(PIN_ESP8285_MODE, OUTPUT);
+  digitalWrite(PIN_ESP8285_MODE, HIGH);     // Prepare for normal start
+}
+
+// Do a HW reset by applying a low pulse to the reset line for 1mSec
+void Challenger2040WiFiClass::doHWReset() {
+  digitalWrite(PIN_ESP8285_RST, LOW);       // Hold ESP8285 in reset
+  delay(1);
+  digitalWrite(PIN_ESP8285_RST, HIGH);      // Release ESP8285 reset
+}
+
+// Set the mode flag high to indicate normal run operation and do a HW
+// reset.
+void Challenger2040WiFiClass::runReset() {  // Prepare ESP8285 for normal op
+  digitalWrite(PIN_ESP8285_MODE, HIGH);     // Prepare for normal start
+  doHWReset();
+}
+
+// Set the mode flag low to indicate flash operation and do a HW
+// reset.
+void Challenger2040WiFiClass::flashReset() { // Prepare ESP8285 for flashing
+  digitalWrite(PIN_ESP8285_MODE, LOW);       // Prepare for normal start
+  doHWReset();
+}
+
+// Wait for the modem to reply with a "ready" prompt. This can be done
+// after a sw or hw reset have been performed to ensure that the AT
+// interpreter is up and running.
+bool Challenger2040WiFiClass::waitForReady() {
+  int timeout = 20;                         // Aprox max 2 sec
+
+  Serial2.begin(DEFAULT_ESP8285_BAUDRATE);
+  Serial2.setTimeout(100);
+  String rdy = Serial2.readStringUntil('\n');
+  while(!rdy.startsWith("ready") && timeout--) {
+    rdy = Serial2.readStringUntil('\n');
+  }
+  Serial2.setTimeout(1000);  // Reset default timeout to 1000
+  if (timeout)
+    return true;
+  return false;
+}
+
+// Reset the ESP8285 and wait for the "ready" prompt to be returned.
+bool Challenger2040WiFiClass::reset() {
+  runReset();
+  return waitForReady();
+}
+
+// Checks to see if the modem responds to the "AT" poll command.
+bool Challenger2040WiFiClass::isAlive() {
+  int timeout = 5;
+
+  Serial2.setTimeout(250);
+  Serial2.println(F("AT"));
+  String rdy = Serial2.readStringUntil('\n');
+  while(!rdy.startsWith(F("OK")) && timeout--) {
+    rdy = Serial2.readStringUntil('\n');
+  }
+  Serial2.setTimeout(1000);
+
+  if (timeout)
+    return true;
+  return false;
+}
+
+// Change the baud rate of the ESP8285 as well as the local UART.
+// No checking is done on the input baud rate so the user must know what
+// baud rates are valid. The function ends by checking if the ESP8285 is
+// reachable by doing an "AT" poll.
+bool Challenger2040WiFiClass::changeBaudRate(int baud) {
+  Serial2.print(F("AT+UART_CUR="));
+  Serial2.print(baud);
+  Serial2.println(F(",8,1,0,0"));
+  delay(100);
+  Serial2.end();
+  Serial2.begin(baud);
+  return isAlive();
+}
+
+Challenger2040WiFiClass Challenger2040WiFi;

variants/challenger_2040_wifi/ChallengerWiFi.h

+/*
+    ESP8285 helper class for the Challenger RP2040 WiFi boards
+
+    Copyright (c) 2021 P. Oldberg <pontus@ilabs.se>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+#pragma once
+
+#define DEFAULT_ESP8285_BAUDRATE      115200
+
+class Challenger2040WiFiClass {
+  public:
+    Challenger2040WiFiClass();
+    void doHWReset();
+    void runReset();
+    void flashReset();
+    bool waitForReady();
+    bool reset();
+    bool isAlive();
+    bool changeBaudRate(int baud);
+};
+
+extern Challenger2040WiFiClass Challenger2040WiFi;