From 1a64241f92251f3ed16ae54afd020a416565bf74 Mon Sep 17 00:00:00 2001
From: Uri Shaked
Date: Thu, 30 Jan 2020 20:21:31 +0200
Subject: feat(twi): partial TWI master implementation #10

---
 src/twi.spec.ts | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 src/twi.spec.ts

(limited to 'src/twi.spec.ts')

diff --git a/src/twi.spec.ts b/src/twi.spec.ts
new file mode 100644
index 0000000..dacd958
--- /dev/null
+++ b/src/twi.spec.ts
@@ -0,0 +1,22 @@
+import { CPU } from './cpu';
+import { AVRTWI, twiConfig } from './twi';
+
+const FREQ_16MHZ = 16e6;
+
+describe('TWI', () => {
+  it('should correctly calculate the sclFrequency from TWBR', () => {
+    const cpu = new CPU(new Uint16Array(1024));
+    const twi = new AVRTWI(cpu, twiConfig, FREQ_16MHZ);
+    cpu.writeData(0xb8, 0x48); // TWBR <- 0x48
+    cpu.writeData(0xb9, 0); // TWSR <- 0 (prescaler: 1)
+    expect(twi.sclFrequency).toEqual(100000);
+  });
+
+  it('should take the prescaler into consideration when calculating sclFrequency', () => {
+    const cpu = new CPU(new Uint16Array(1024));
+    const twi = new AVRTWI(cpu, twiConfig, FREQ_16MHZ);
+    cpu.writeData(0xb8, 0x03); // TWBR <- 0x03
+    cpu.writeData(0xb9, 0x01); // TWSR <- 1 (prescaler: 4)
+    expect(twi.sclFrequency).toEqual(400000);
+  });
+});
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