varpa: initial public commit

1 files changed, 101 insertions, 0 deletions

diff --git a/firmware/src/driver/mcp4725.c b/firmware/src/driver/mcp4725.c
new file mode 100644
index 0000000..4cb9bd6
--- /dev/null
+++ b/firmware/src/driver/mcp4725.c
@@ -0,0 +1,101 @@
+/**
+ * 
+ * Author: Dylan Muller
+ * Copyright (c) 2025 
+ * All rights reserved.
+ * 
+ * - Commercial/IP use prohibited.
+ * - Attribution required.
+ * See License.txt
+ *
+ */
+
+#include "setup.h"
+
+#include "peripheral/twi.h"
+#include "driver/mcp4725.h"
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+
+void dac_init(uint16_t init_value)
+{
+        dac_write(MCP4725_ID_GATE_VOLT, init_value, 0);
+        dac_write(MCP4725_ID_DRAIN_VOLT, init_value, 0);
+
+        _delay_ms(TRANSACT_DELAY_MS);
+}
+
+void dac_write(
+    uint8_t id,
+    uint16_t value,
+    uint8_t conv_bypass
+)
+{
+    uint8_t dev_addr = 0x0;
+    uint8_t cmd_buf[2] = {0x0, 0x0};
+    uint8_t drain_mode = 0x0;
+
+    switch(id)
+    {
+        case MCP4725_ID_GATE_VOLT:
+            dev_addr = TWI_ADDRESS_W(MCP4725_DEV_GATE_VOLT_ADDR);
+            break;
+        case MCP4725_ID_DRAIN_VOLT:
+            dev_addr = TWI_ADDRESS_W(MCP4725_DEV_DRAIN_VOLT_ADDR);
+            drain_mode = 1;
+            break;
+    }
+
+    if (conv_bypass == 0)
+    {
+        if (drain_mode == 1)
+        {
+            value = (uint16_t)(((uint32_t)value * 10)/MCP4725_DRAIN_GAIN);
+        }
+    }
+
+    cmd_buf[0] = ((value >> 8) & 0xF) | MCP4725_BIT_PD0(0) | MCP4725_BIT_PD1(0);
+    cmd_buf[1] = value & 0xFF;
+
+    twi_start(dev_addr, cmd_buf, sizeof(cmd_buf));
+    twi_flush();
+}
+
+uint16_t dac_read(
+    uint8_t id,
+    uint8_t conv_bypass
+)
+{
+    uint8_t dev_addr = 0x0;
+    uint8_t cmd_buf[3] = {0x0, 0x0, 0x0};
+    uint16_t value = 0x0;
+    uint8_t drain_mode = 0x0;
+
+    switch(id)
+    {
+        case MCP4725_ID_GATE_VOLT:
+            dev_addr = TWI_ADDRESS_R(MCP4725_DEV_GATE_VOLT_ADDR);
+            break;
+        case MCP4725_ID_DRAIN_VOLT:
+            dev_addr = TWI_ADDRESS_R(MCP4725_DEV_DRAIN_VOLT_ADDR);
+            drain_mode = 1;
+            break;
+    }
+
+    twi_start(dev_addr, cmd_buf, sizeof(cmd_buf));
+    twi_flush();
+
+    value = (((uint16_t)cmd_buf[1]) << 4) | (cmd_buf[2] >> 4);
+
+    if (conv_bypass == 0)
+    {
+        if (drain_mode)
+        {
+            value = (uint16_t)(((uint32_t)value * MCP4725_DRAIN_GAIN)/10);
+        }
+    }
+
+    return (value & 0xFFF); 
+}