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主题中讨论的其他器件：DAC8812、 OPA2277、 DAC8811número ó n de 压差：DAC8812.
herramienta/软件：
您好！
我对 DAC 输出有一个问题：它始终保持在0伏。 为了提供一些背景信息、我使用 DAC8812和两个 OPA2277 (基于 DAC8811的双极输出电路)对两个双极电压源进行了设计和原型设计。
LDAC#：GPIO04
CS#：GPIO05
GPIO16号：RS
CLK：GPIO18
SDI：GPIO23
MSB： 接地
VDD： ESP32的3、3V
VREFX：2.5V 电源
+VS：10V 电源
-VS：-10 V 电源
Estas son las señales ó n que VEO en el osciloscopio: 
第一个信号：
黄色信号：CS#
蓝色信号：CLK
第二个信号：
黄色信号：LDAC#(持续时间大于20 ns)
蓝色信号：CS#
第三个信号：
黄色信号：CLK
蓝色信号：SDI (发送0b1111111111111111)
SPI 通信最初看起来不错、但我不明白输出为什么与0V 不同
/*Demo codes for testing DAC8812*/
#include <Arduino.h>
#include <SPI.h>
//Full functionality demo code
// DAC8812 Pin Definitions
#define CS_PIN 5 // Chip Select (CS) pin
#define LDAC_PIN 4 // Load DAC (LDAC) pin
#define RS_PIN 16 // Reset (RS) pin
// SPI settings
SPISettings DAC8812_settings(1000000, MSBFIRST, SPI_MODE0);
void setup() {
// Initialize Serial Monitor for debugging
Serial.begin(115200);
// Configure SPI
SPI.begin(); // Initializes the SPI bus
// Configure control pins
pinMode(CS_PIN, OUTPUT);
pinMode(LDAC_PIN, OUTPUT);
pinMode(RS_PIN, OUTPUT);
// Set control pins to default states
digitalWrite(CS_PIN, HIGH); // CS should be high when not communicating
digitalWrite(LDAC_PIN, HIGH); // LDAC high to not update outputs
digitalWrite(RS_PIN, HIGH); // RS high to avoid reset
Serial.println("DAC channels updated!");
}
void loop() {
// Your main loop code can go here
//digitalWrite(RS_PIN, HIGH); // RS high to avoid reset
programDAC8812(1, 0xFFFF); // Set channel A to midscale (32768, mid value of 2^16)
// programDAC8812(2, 0x4000);
}
void programDAC8812(byte channel, uint16_t value) {
uint32_t command = 0x00000; // Nota: el tamaño debe ser al menos 18 bits, por eso se usa un uint32_t
// Configure the command based on the selected channel
if (channel == 1) {
command = 0b11 << 16; // Set DAC A (A1:A0 = 01)
} else if (channel == 2) {
command = 0b10 << 16; // Set DAC B (A1:A0 = 10)
}
// Combine the channel bits with the value
command |= (value & 0xFFFF); // Set the 16-bit value
// Print the full 18-bit command in binary
Serial.print("Channel: ");
Serial.print(channel);
Serial.print(", Value: 0x");
Serial.print(value, HEX);
Serial.print(" -> Command: 0b");
for (int i = 17; i >= 0; i--) {
Serial.print((command >> i) & 1);
}
Serial.println();
// Begin SPI communication
SPI.beginTransaction(DAC8812_settings);
digitalWrite(CS_PIN, HIGH);
digitalWrite(CS_PIN, LOW);
// Split the 18-bit command into SPI transfers
uint16_t firstPart = (command >> 2) & 0xFFFF; // Extract the upper 16 bits
uint8_t secondPart = (command & 0x3) << 6; // Extract the lower 2 bits and shift them
// Print the parts being transferred
Serial.print("SPI.transfer16: 0x");
Serial.println(firstPart, HEX);
Serial.print("SPI.transfer: 0x");
Serial.println(secondPart, HEX);
// Send the data via SPI
//SPI.transfer16(firstPart);
uint8_t byte1 = (command >> 10) & 0xFF; // Primeros 8 bits (de B17 a B10)
uint8_t byte2 = (command >> 2) & 0xFF; // Siguientes 8 bits (de B9 a B2)
uint8_t byte3 = (command & 0x3) << 6; // Últimos 2 bits (de B1 a B0) desplazados a la izquierda
// Enviar cada parte
SPI.transfer(byte1);
SPI.transfer(byte2);
SPI.transfer(byte3);
digitalWrite(CS_PIN, HIGH); // End SPI communication
digitalWrite(LDAC_PIN, LOW);
// Short delay for LDAC pulse
digitalWrite(LDAC_PIN, HIGH);
//digitalWrite(CS_PIN, LOW);
SPI.endTransaction();
}我希望你能帮我。
此致、Omar
