D3AA simulator

1 files changed, 30 insertions, 0 deletions

diff --git a/src/peripherals/avrdx-dac.ts b/src/peripherals/avrdx-dac.ts
new file mode 100644
index 0000000..d4843ca
--- /dev/null
+++ b/src/peripherals/avrdx-dac.ts
@@ -0,0 +1,30 @@
+// AVR-Dx DAC0 peripheral
+// 10-bit DAC with output enable, used for LED brightness control on the D3AA
+
+import type { CPU } from 'avr8js/cpu/cpu';
+
+const CTRLA = 0x00;
+// const DATA  = 0x02; // 16-bit (DATAL + DATAH)
+const DATAL = 0x02;
+const DATAH = 0x03;
+
+const ENABLE_bm = 0x01;
+const OUTEN_bm  = 0x40;
+
+export class AVRDxDAC {
+  constructor(private cpu: CPU, private base: number) {
+  }
+
+  /** Whether DAC is enabled and output is enabled */
+  get enabled(): boolean {
+    const ctrla = this.cpu.data[this.base + CTRLA];
+    return !!(ctrla & ENABLE_bm) && !!(ctrla & OUTEN_bm);
+  }
+
+  /** Get the current 10-bit DAC value (0-1023).
+   *  DAC0.DATA is left-aligned: the 10-bit value sits in bits [15:6]. */
+  get value(): number {
+    const raw16 = this.cpu.data[this.base + DATAL] | (this.cpu.data[this.base + DATAH] << 8);
+    return raw16 >> 6;
+  }
+}