Using two SPI buses

[wcpettus]

I'm trying to configure an ESP32-Gateway to talk with an SPI device. I feel I must be missing something about the hardware configuration.

I've started with the SPI_Multiple_Buses example code, but the default pins for VSPI (18,19,23,5) and HSPI (14,12,13,15) are mostly not exposed to the extension headers. Consulting the schematic (I'm using a rev C) I have access to
GPIO 5,16,17,32,33
GPI 34,35,36,39
Debug only 6,7,8,9,10,11

I've verified I can see SPI signals on the 5 pins I have access to, I'm explicitly told to skip the 6 SD-related pins, and the other 4 are input only? That seems like a waste of header real estate, and how can one operate two SPI buses concurrently (alternatively this would limit the number of SS pins for a single SPI bus)?

Probably some trivial ignorance on my part?

[DrTester0x42]

@wcpettus This is a good question have you found the answer to this yet?

Looking at the boards headers I am not seeing any dedicated SPI ports. What are your thoughts? @TsvetanUsunov

[wcpettus]

I would love to know the answer. I also tried asking on the forums but never heard anything back:
https://www.olimex.com/forum/index.php?topic=7090.0

[drdelgado]

Hello

[drdelgado]

@wcpettus Just out of curiosity what did you use for your CLK? GPIO6?

[wcpettus]

I used GPIO32 - I didn't want to touch GPIO6 since it's one of the reserved for debug only pins that I don't understand. Beyond that my choice for which was MISO/MOSI/CLK/CS were pretty random.

[drdelgado]

@wcpettus were you able to get SPI peripheral + ethernet functionality working?

[wcpettus]

that's right - I've been using an SPI to communicate with an ADC and ethernet to readout the data

[drdelgado]

@wcpettus any chance you'd be willing to share your code?

[fightforlife]

I would also love to hear how an external SPI Device can be User with this Board? ( HSPI and VSPI seems Not to be available in the Header)

[wcpettus]

Prefaced with the disclaimer that I don't think this is the final code version, but this is what I found digging through old code directories; clearly I should have documented better and answered 3.5 years ago when the original question was fresh (or made the undergrad who was doing the implementation do so :D)

This at least seems to work with an ADC, use SPI, and have ethernet functionality.

include <MCP3XXX.h>
 #include <ETH.h>

 //Define ADC interfaces
 #define CS_PIN 5     // ESP8266 default SPI pins
 #define CLK_PIN 32  // Should work with any other GPIO pins, since the library does not formally
 #define MOSI_PIN 16   // use SPI, but rather performs pin bit banging to emulate SPI communication.
 #define MISO_PIN 17   //
 MCP3204 adc;

 //Define network settings
 static bool eth_connected = false;
 IPAddress ip(10, 0, 0, 2);
 IPAddress gate(10, 0, 0, 1);
 IPAddress mask(255, 255, 255, 0);

 //Define telnet server parameters
 #define MAX_SRV_CLIENTS 4
 WiFiServer server(23);
 WiFiClient serverClients[MAX_SRV_CLIENTS];
 const byte charLim = 32;
 const char terminator = '\n';

 void WiFiEvent(WiFiEvent_t event)
 {
   switch (event) {
     case SYSTEM_EVENT_ETH_START:
       Serial.println("ETH Started");
       //set eth hostname here
       ETH.setHostname("arduino1");
       break;
     case SYSTEM_EVENT_ETH_CONNECTED:
       Serial.println("ETH Connected");
       break;
     case SYSTEM_EVENT_ETH_GOT_IP:
       Serial.print("ETH MAC: ");
       Serial.print(ETH.macAddress());
       Serial.print(", IPv4: ");
       Serial.print(ETH.localIP());
       if (ETH.fullDuplex()) Serial.print(", FULL_DUPLEX");
       Serial.print(", ");
       Serial.print(ETH.linkSpeed());
       Serial.println("Mbps");
       eth_connected = true;
       break;
     case SYSTEM_EVENT_ETH_DISCONNECTED:
       Serial.println("ETH Disconnected");
       eth_connected = false;
       break;
     case SYSTEM_EVENT_ETH_STOP:
       Serial.println("ETH Stopped");
       eth_connected = false;
       break;
     default:
       break;
   }
 }

 void setup()
 {
   Serial.begin(115200);

   WiFi.onEvent(WiFiEvent);
   ETH.begin();
   ETH.config(ip, gate, mask, gate);
   server.begin();
   server.setNoDelay(true);
   Serial.println("network and server setup initialized");
   adc.begin(CS_PIN, MOSI_PIN, MISO_PIN, CLK_PIN);
   Serial.println("setup done");
 }

 // function to handle new connections
 void handle_connection()
 {
   uint8_t i;
   if (server.hasClient()) {
     for (i = 0; i < MAX_SRV_CLIENTS; i++) {
       //find free/disconnected spot
       if (!serverClients[i] || !serverClients[i].connected()) {
         if (serverClients[i]) serverClients[i].stop();
         serverClients[i] = server.available();
         if (!serverClients[i]) Serial.println("available broken");
         Serial.print("New client: ");
         Serial.print(i); Serial.print(' ');
         Serial.println(serverClients[i].remoteIP());
         serverClients[i].print("You are connection ");
         serverClients[i].print(i); serverClients[i].print(" to ");
         serverClients[i].println(ETH.getHostname());
         serverClients[i].print(">");
         //flush input buffer on connection
         while (serverClients[i].available()) serverClients[i].read();
         break;
       }
     }
     if (i >= MAX_SRV_CLIENTS) {
       //no free/disconnected spot so reject
       server.available().stop();
     }
   }
 }

 // function to read commands from controls
 void read_connection()
 {
   uint8_t i;
   for (i = 0; i < MAX_SRV_CLIENTS; i++) {
     if (serverClients[i] && serverClients[i].connected()) {
       if (serverClients[i].available()) {
         char input[charLim + 2];
         uint8_t nRx = 0;
         bool incomplete = true;
         while (serverClients[i].available()) {
           input[nRx] = serverClients[i].read();
           if (input[nRx] == terminator) {
             input[nRx + 2] = '\0';
             parse_command(&serverClients[i], input);
             incomplete = false;
             break;
           } else if (nRx < charLim) {
             nRx ++;
           }
         }
         if (incomplete) serverClients[i].println("ERROR: Incomplete transmission");
       }
     }
     else {
       if (serverClients[i]) serverClients[i].stop();
     }
   }
 }

 // funtion to interpret received command
 void parse_command(WiFiClient *client, char *input)
 {
   Serial.print("Received command: ");
   Serial.println(input);
   client->print(input);
   switch (input[0]) {
     // READ option, <RN>, return ADC input N value
     case 'R':
       measurement(client, input[1] - '0'); // expect a uint8_t
       break;
     // TEST option, <T> return 1
     case 'T':
       client->println(1);
       break;
     default:
       client->println("ERROR: Invalid command");
       break;
   }
   client->print(">");
 }

 // function to record measurements from a coldhead ADC
 void measurement(WiFiClient *client, uint8_t chanID)
 {
   if (chanID > 3) return;
   client->print("Ch: ");
   client->print(chanID);
   client->print("; Val: ");
   client->println(adc.analogRead(chanID));
 }

 void loop()
 {
   if (eth_connected) {
     //check if there are any new clients
     handle_connection();
     //check clients for data
     read_connection();
   } else {
     Serial.println("ETH not connected!");
     delay(100);
     for (uint8_t i = 0; i < MAX_SRV_CLIENTS; i++) {
       if (serverClients[i]) serverClients[i].stop();
     }
   }
 }

[fightforlife]

Thanks you very much for the example of using Software SPI/bitbanging.
While checking the Docs I found that the Hardware HSPI Pins are available on the header in newer Board revisions. (But then ofcourse you can Not use the sdcard at the same time).