ESP8266 Community Forum

Hi - first of all I'm using the wemos D1 mini is that not a cracking little board. Top job.
If I have posted in the wrong group - sorry..

OK I'm having some proper nightmares in connecting the WEMOS mini via SPI to a NFC board. Any advice be really welcome.

This is the board http://www.solutions-cubed.com/bm019/
I've used the UNO example provided to connect to the Uno but as the UNO is 5v and the Wemos is 3.3v I've not added any resistors, although I have tried a 10k pull up on the SS line - made no difference.

BM019 to WEMOS
1 DOUT - no used
2 DIN - D1 (IO)
3 SS - D7
4 MISO - D6 (MISO)
5 MOSI - D7 (MOSI)
6 SCK - D5 (SCK)
7 SS_0 - tied to 3.3v so BM019 uses SPI
8 VDD
9 VIN - 5v
10 GND - Gnd

The code is quite specific in the way communication is set up on the BM019 - this is the example code used to connect to the Uno. I've changed the SS and IRQ pin numbers. But still nothing.. is there is a different include SPI I'm supposed to use with the Wemos?

Look forward to any comments.

/*
NFC Communication with the Solutions Cubed, LLC BM019
and an Arduino Uno. The BM019 is a module that
carries ST Micro's CR95HF, a serial to NFC converter.

Wiring:
Arduino BM019
IRQ: Pin 9 (now 13) DIN: pin 2
SS: pin 10 (now 5) SS: pin 3
MOSI: pin 11 (now 13) MOSI: pin 5
MISO: pin 12 (now 12) MISO: pin4
SCK: pin 13 (now 14) SCK: pin 6

*/

// the sensor communicates using SPI, so include the library:
#include <SPI.h>

const int SSPin = 13; // Slave Select pin
const int IRQPin = 5; // Sends wake-up pulse
byte TXBuffer[40]; // transmit buffer
byte RXBuffer[40]; // receive buffer
byte NFCReady = 0; // used to track NFC state


void setup() {
pinMode(IRQPin, OUTPUT);
digitalWrite(IRQPin, HIGH); // Wake up pulse
pinMode(SSPin, OUTPUT);
digitalWrite(SSPin, HIGH);

Serial.begin(9600);
SPI.begin();
SPI.setDataMode(SPI_MODE0);
SPI.setBitOrder(MSBFIRST);
SPI.setClockDivider(SPI_CLOCK_DIV32);

// The CR95HF requires a wakeup pulse on its IRQ_IN pin
// before it will select UART or SPI mode. The IRQ_IN pin
// is also the UART RX pin for DIN on the BM019 board.

delay(10); // send a wake up
digitalWrite(IRQPin, LOW); // pulse to put the
delayMicroseconds(100); // BM019 into SPI
digitalWrite(IRQPin, HIGH); // mode
delay(10);
}

/* IDN_Command identifies the CR95HF connected to the Arduino.
This requires three steps.
1. send command
2. poll to see if CR95HF has data
3. read the response

If the correct response is received the serial monitor is used
to display the CR95HF ID number and CRC code. This rountine is
not that useful in using the NFC functions, but is a good way to
verify connections to the CR95HF.
*/
void IDN_Command()
{
byte i = 0;

// step 1 send the command
digitalWrite(SSPin, LOW);
SPI.transfer(0); // SPI control byte to send command to CR95HF
SPI.transfer(1); // IDN command
SPI.transfer(0); // length of data that follows is 0
digitalWrite(SSPin, HIGH);
delay(1);

// step 2, poll for data ready
// data is ready when a read byte
// has bit 3 set (ex: B'0000 1000')

digitalWrite(SSPin, LOW);
while(RXBuffer[0] != 8)
{
RXBuffer[0] = SPI.transfer(0x03); // Write 3 until
RXBuffer[0] = RXBuffer[0] & 0x08; // bit 3 is set
}
digitalWrite(SSPin, HIGH);
delay(1);


// step 3, read the data
digitalWrite(SSPin, LOW);
SPI.transfer(0x02); // SPI control byte for read
RXBuffer[0] = SPI.transfer(0); // response code
RXBuffer[1] = SPI.transfer(0); // length of data
for (i=0;i<RXBuffer[1];i++)
RXBuffer[i+2]=SPI.transfer(0); // data
digitalWrite(SSPin, HIGH);
delay(1);

if ((RXBuffer[0] == 0) & (RXBuffer[1] == 15))
{
Serial.println("IDN COMMAND-"); //
Serial.print("RESPONSE CODE: ");
Serial.print(RXBuffer[0]);
Serial.print(" LENGTH: ");
Serial.println(RXBuffer[1]);
Serial.print("DEVICE ID: ");
for(i=2;i<(RXBuffer[1]);i++)
{
Serial.print(RXBuffer[i],HEX);
Serial.print(" ");
}
Serial.println(" ");
Serial.print("ROM CRC: ");
Serial.print(RXBuffer[RXBuffer[1]],HEX);
Serial.print(RXBuffer[RXBuffer[1]+1],HEX);
Serial.println(" ");
}
else
Serial.println("BAD RESPONSE TO IDN COMMAND!");

Serial.println(" ");
}

/* SetProtocol_Command programs the CR95HF for
ISO/IEC 15693 operation.

This requires three steps.
1. send command
2. poll to see if CR95HF has data
3. read the response

If the correct response is received the serial monitor is used
to display successful programming.
*/
void SetProtocol_Command()
{
byte i = 0;

// step 1 send the command
digitalWrite(SSPin, LOW);
SPI.transfer(0x00); // SPI control byte to send command to CR95HF
SPI.transfer(0x02); // Set protocol command
SPI.transfer(0x02); // length of data to follow
SPI.transfer(0x01); // code for ISO/IEC 15693
SPI.transfer(0x0D); // Wait for SOF, 10% modulation, append CRC
digitalWrite(SSPin, HIGH);
delay(1);

// step 2, poll for data ready

digitalWrite(SSPin, LOW);
while(RXBuffer[0] != 8)
{
RXBuffer[0] = SPI.transfer(0x03); // Write 3 until
RXBuffer[0] = RXBuffer[0] & 0x08; // bit 3 is set
}
digitalWrite(SSPin, HIGH);
delay(1);

// step 3, read the data
digitalWrite(SSPin, LOW);
SPI.transfer(0x02); // SPI control byte for read
RXBuffer[0] = SPI.transfer(0); // response code
RXBuffer[1] = SPI.transfer(0); // length of data
digitalWrite(SSPin, HIGH);

if ((RXBuffer[0] == 0) & (RXBuffer[1] == 0))
{
Serial.println("PROTOCOL SET-"); //
NFCReady = 1; // NFC is ready
}
else
{
Serial.println("BAD RESPONSE TO SET PROTOCOL");
NFCReady = 0; // NFC not ready
}
Serial.println(" ");
}

/* Inventory_Command chekcs to see if an RF
tag is in range of the BM019.

This requires three steps.
1. send command
2. poll to see if CR95HF has data
3. read the response

If the correct response is received the serial monitor is used
to display the the RF tag's universal ID.
*/
void Inventory_Command()
{
byte i = 0;

// step 1 send the command
digitalWrite(SSPin, LOW);
SPI.transfer(0x00); // SPI control byte to send command to CR95HF
SPI.transfer(0x04); // Send Receive CR95HF command
SPI.transfer(0x03); // length of data that follows is 0
SPI.transfer(0x26); // request Flags byte
SPI.transfer(0x01); // Inventory Command for ISO/IEC 15693
SPI.transfer(0x00); // mask length for inventory command
digitalWrite(SSPin, HIGH);
delay(1);

// step 2, poll for data ready
// data is ready when a read byte
// has bit 3 set (ex: B'0000 1000')

digitalWrite(SSPin, LOW);
while(RXBuffer[0] != 8)
{
RXBuffer[0] = SPI.transfer(0x03); // Write 3 until
RXBuffer[0] = RXBuffer[0] & 0x08; // bit 3 is set
}
digitalWrite(SSPin, HIGH);
delay(1);


// step 3, read the data
digitalWrite(SSPin, LOW);
SPI.transfer(0x02); // SPI control byte for read
RXBuffer[0] = SPI.transfer(0); // response code
RXBuffer[1] = SPI.transfer(0); // length of data
for (i=0;i<RXBuffer[1];i++)
RXBuffer[i+2]=SPI.transfer(0); // data
digitalWrite(SSPin, HIGH);
delay(1);

if (RXBuffer[0] == 128)
{
Serial.println("TAG DETECTED");
Serial.print("UID: ");
for(i=11;i>=4;i--)
{
Serial.print(RXBuffer[i],HEX);
Serial.print(" ");
}
Serial.println(" ");
}
else
{
Serial.print("NO TAG IN RANGE - ");
Serial.print("RESPONSE CODE: ");
Serial.println(RXBuffer[0],HEX);
}
Serial.println(" ");
}


void loop() {

if(NFCReady == 0)
{
IDN_Command(); // reads the CR95HF ID
delay(1000);
SetProtocol_Command(); // ISO 15693 settings
delay(1000);
}
else
{
Inventory_Command();
delay(1000);
}

}

The pins assigned in the above code are wrong.. sadly still doesn't work. Does anyone know if the Wemos / ESP8266 works with all SPI modes

Arduino BM019
IRQ: Pin 9 (now 5) DIN: pin 2
SS: pin 10 (now 15) SS: pin 3
MOSI: pin 11 (now 13) MOSI: pin 5
MISO: pin 12 (now 12) MISO: pin4
SCK: pin 13 (now 14) SCK: pin 6

*/

// the sensor communicates using SPI, so include the library:
#include <SPI.h>

const int SSPin = 15; // Slave Select pin
const int IRQPin = 5; // Sends wake-up pulse
byte TXBuffer[40]; // transmit buffer
byte RXBuffer[40]; // receive buffer
byte NFCReady = 0; // used to track NFC state

The SPI pins of the WeMos D1 Mini are the same as plain ESP8266.
In WeMos D1 Mini pins naming, they are :

And with the actual ESP pin mapping, which can be found in esp8266/2.1.0/variants/d1_mini/pins_arduino.h :

Thanks Martyn - cheers I did try using that SS pin. Will try again - very frustrating.
Be interested in thoughts on how to fault find without a scope..