1 files changed, 32 insertions, 0 deletions
diff --git a/src/peripherals/avrdx-vref.ts b/src/peripherals/avrdx-vref.ts
new file mode 100644
index 0000000..0097096
--- /dev/null
+++ b/src/peripherals/avrdx-vref.ts
@@ -0,0 +1,32 @@
+// AVR-Dx VREF peripheral
+// Voltage reference selection for DAC0 and ADC0
+
+import { CPU } from 'avr8js/cpu/cpu';
+
+const ADC0REF = 0;
+const DAC0REF = 2;
+
+const VREF_VOLTAGES = [1.024, 2.048, 2.500, 4.096] as const;
+
+export class AVRDxVREF {
+  constructor(private cpu: CPU, private base: number) {
+  }
+
+  /** Get DAC Vref selection (raw register value) */
+  get dacRef(): number {
+    return this.cpu.data[this.base + DAC0REF] & 0x07;
+  }
+
+  get dacRefVolts(): number {
+    return VREF_VOLTAGES[this.dacRef] ?? 0;
+  }
+
+  /** Get ADC Vref selection (raw register value) */
+  get adcRef(): number {
+    return this.cpu.data[this.base + ADC0REF] & 0x07;
+  }
+
+  get adcRefVolts(): number {
+    return VREF_VOLTAGES[this.adcRef] ?? 0;
+  }
+}