Diff: MCP4801.cpp

Revision:

0:886b1ee1370b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP4801.cpp	Tue Mar 03 20:08:59 2020 +0000
@@ -0,0 +1,59 @@
+#include "mbed.h"
+#include "MCP4801.h"
+
+MCP4801::MCP4801(SPI &spi, PinName ssel, PinName ldacLowPin,PinName shutdownLowPin): _slaveSelectLow(ssel), _ldacLow(ldacLowPin),_shutdownLow(shutdownLowPin){
+  //initialize pins
+    _slaveSelectLow = 1;
+    _spi = &spi;
+    _spi->format(8,0);
+    _spi->frequency(1000000);
+    if(_ldacLow.is_connected()) _ldacLow = 0;
+    if(_shutdownLow.is_connected()) _shutdownLow = 0;
+}
+
+void MCP4801::setOutput_state(uint8_t state, bool soft){
+    if(soft){
+        shutdown = state;
+    }else{
+        if(_shutdownLow.is_connected()) _shutdownLow = state;
+    }
+    
+}
+
+void MCP4801::updateOutput(){
+    if(_ldacLow.is_connected()){
+        _ldacLow = 1;
+        wait_us(5000);
+        _ldacLow = 0;
+    }
+}
+
+
+int MCP4801::setVOutput(float voltage){
+    uint8_t gain_bit = 0;
+    unsigned short int value = 0;
+    int error;
+  
+    //auto choose range
+    if(voltage < VREF){ 
+        gain_bit = 1; //gain 1
+        value = voltage/VREF*RES8BIT;
+    }else{ 
+        gain_bit = 0; //gain 2
+        value = 0.5*voltage/VREF*RES8BIT;
+    } 
+    char packet[]= {0x00,0x00};
+    packet[0] = value >> 4;
+    packet[1] = value << 4;
+    packet[0] |= shutdown << 4;                             //shutdown - output state
+    packet[0] |= gain_bit << 5;                             //gain
+    
+    _slaveSelectLow = 0;                                    //set chip as listener 
+    error = _spi->write(packet, sizeof(packet), NULL, 0);   //send packet (const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length)
+    _slaveSelectLow = 1;                                    //release chip select
+    if(_ldacLow.is_connected()) _ldacLow = 0;               //pull latch down
+    wait_us(1);
+    if(_ldacLow.is_connected()) _ldacLow = 1;               //pull latch up
+    
+    return error;
+}
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