Part Number: ADS1299EEGFE-PDK
Other Parts Discussed in Thread: ADS1299
Hi there,
My name is Mike and im a final year Auckland University of Technology student currently working on a multi-disiplinary project which is a waerable data logger/acqusition system or device.
In my team im the one who is responsible for the hardware testing and programming which has been a task and I just need some guidance from people who have faced the same issue as me.
I have managed to connect J3 pins of the ADS1299 (CS, CLK, DIN, DOUT, RESET, START, DRDY, GND) to my ESP32 designated pins as follows
PIN_CS 5
PIN_DRDY 4
PIN_MOSI 23
PIN_MISO 21
PIN_SCLK 18
PIN_START 13
PIN_RESET 26
After running a code that i had got from the help of Claude, I am expecting to get a reading of 0x3E which is mentioned on the ADS1299 datasheet for SPI communication.
this occures when DRDY is toggling from 0 and 1 however in my case it has been stuck on HIGH for a long time.
I have tried separating the MMBO from the ADS1299(top layer PCB) thinking it might be going through a conflict of SPI bus control but at the same time I need them connected for correct power supply.
I have also tired powering the ADS1299 with the 5V of the ESP32(VIN) but im affraid it isn't sufficent enough or has inconsistency due to poor jumper wires. However, when trying both i still had 0xFF reading which indicates DRDY never switched/toggled.
After running a code that i had got from the help of Claude, I am expecting to get a reading of 0x3E which is mentioned on the ADS1299 datasheet for SPI communication.
this occures when DRDY is toggling from 0 and 1 however in my case it has been stuck on HIGH for a long time.
I have tried separating the MMBO from the ADS1299(top layer PCB) thinking it might be going through a conflict of SPI bus control but at the same time I need them connected for correct power supply.
I have also tired powering the ADS1299 with the 5V of the ESP32(VIN) but im affraid it isn't sufficent enough or has inconsistency due to poor jumper wires. However, when trying both i still had 0xFF reading which indicates DRDY never switched/toggled.
#include <Arduino.h>
#include <SPI.h>
#define PIN_CS 5
#define PIN_DRDY 4
#define PIN_MOSI 23
#define PIN_MISO 21
#define PIN_SCLK 18
#define PIN_START 13
#define PIN_RESET 26
SPISettings ads_spi(250000, MSBFIRST, SPI_MODE1);
void sendSDATAC() {
SPI.beginTransaction(ads_spi);
digitalWrite(PIN_CS, LOW);
delayMicroseconds(10);
SPI.transfer(0x11); // SDATAC command
delayMicroseconds(10); // wait 4+ tCLK BEFORE releasing CS
digitalWrite(PIN_CS, HIGH);
SPI.endTransaction();
delayMicroseconds(10); // wait 4+ tCLK after CS goes high
delay(10); // extra settling time
}
byte readRegister(byte address) {
byte value = 0;
SPI.beginTransaction(ads_spi);
digitalWrite(PIN_CS, LOW);
delayMicroseconds(10);
SPI.transfer(0x20 | address); // RREG command
delayMicroseconds(10);
SPI.transfer(0x00); // read 1 register
delayMicroseconds(10);
value = SPI.transfer(0x00); // get value
delayMicroseconds(10);
digitalWrite(PIN_CS, HIGH);
SPI.endTransaction();
delayMicroseconds(10);
return value;
}
void sendCommand(byte cmd) {
SPI.beginTransaction(ads_spi);
digitalWrite(PIN_CS, LOW);
delayMicroseconds(10);
SPI.transfer(cmd);
delayMicroseconds(10);
digitalWrite(PIN_CS, HIGH);
SPI.endTransaction();
delayMicroseconds(10);
}
void setup() {
Serial.begin(921600);
delay(5000);
pinMode(PIN_CS, OUTPUT); digitalWrite(PIN_CS, HIGH);
pinMode(PIN_RESET, OUTPUT); digitalWrite(PIN_RESET, LOW);
pinMode(PIN_START, OUTPUT); digitalWrite(PIN_START, LOW);
pinMode(PIN_DRDY, INPUT);
SPI.begin(PIN_SCLK, PIN_MISO, PIN_MOSI, PIN_CS);
Serial.println("=== ADS1299 ID Test (TI Forum Fix) ===");
// Step 1 - Hardware reset
Serial.println("Step 1: RESET LOW 500ms...");
digitalWrite(PIN_RESET, LOW);
delay(500);
Serial.println("Step 2: RESET HIGH...");
digitalWrite(PIN_RESET, HIGH);
delay(1000); // wait for chip to fully boot
// Step 3 - Send SDATAC multiple times with proper timing
Serial.println("Step 3: Sending SDATAC x5 with proper tCLK delays...");
for (int i = 0; i < 5; i++) {
sendSDATAC();
delay(50);
}
delay(100);
// Step 4 - Pull START HIGH
Serial.println("Step 4: START HIGH...");
digitalWrite(PIN_START, HIGH);
delay(100);
// Step 5 - Watch DRDY
Serial.println("Step 5: Watching DRDY for 3 seconds...");
int changes = 0;
int last = digitalRead(PIN_DRDY);
unsigned long t = millis();
while (millis() - t < 3000) {
int cur = digitalRead(PIN_DRDY);
if (cur != last) {
changes++;
Serial.printf(" DRDY -> %d at %lums\n", cur, millis() - t);
last = cur;
if (changes >= 6) break;
}
}
Serial.printf("DRDY changes: %d\n", changes);
Serial.println(changes > 0 ? "Chip IS converting!" : "Chip not converting");
// Step 6 - Read ID register 20 times
Serial.println("\nStep 6: Reading ID register 20 times:");
for (int i = 0; i < 20; i++) {
delay(200);
byte id = readRegister(0x00);
Serial.printf(" Read %d: 0x%02X %s\n",
i+1, id,
((id & 0x1F) == 0x1E) ? "<-- GOT IT!" : "");
if ((id & 0x1F) == 0x1E) {
Serial.println("SUCCESS - ADS1299 communication established!");
break;
}
}
// Step 7 - MISO state
pinMode(PIN_MISO, INPUT);
Serial.printf("\nMISO idle: %s\n",
digitalRead(PIN_MISO) ? "HIGH" : "LOW");
}
void loop() {}
the below is the reading I base my work on which is from the serial monitor
the below is the reading I base my work on which is from the serial monitor
=== ADS1299 ID Test (TI Forum Fix) ===
Step 1: RESET LOW 500ms...
Step 2: RESET HIGH...
Step 3: Sending SDATAC x5 with proper tCLK delays...
Step 4: START HIGH...
Step 5: Watching DRDY for 3 seconds...
DRDY changes: 0
Chip not converting
Step 6: Reading ID register 20 times:
Read 1: 0xFF
Read 2: 0xFF
Read 3: 0xFF
Read 4: 0xFF
Read 5: 0xFF
Read 6: 0xFF
Read 7: 0xFF
Read 8: 0xFF
Read 9: 0xFF
Read 10: 0xFF
MISO idle: HIGH
Thank you for reading through all of this and I appriciate fortaking your time.
look forward to any support or feedback i can get.
kind regards
Mike.