1 files changed, 42 insertions, 0 deletions
diff --git a/fw/mcp9801.c b/fw/mcp9801.c
new file mode 100644
index 0000000..76aac1e
--- /dev/null
+++ b/fw/mcp9801.c
@@ -0,0 +1,42 @@
+/* 8seg LED display driver firmware
+ * Copyright (C) 2018 Sebastian Götte <code@jaseg.net>
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "global.h"
+#include "i2c.h"
+#include "mcp9801.h"
+
+void mcp9801_init()
+{
+    uint8_t config = MCP9801_ONESHOT_OFF | MCP9801_RES_12BIT | MCP9801_FAULT_QUEUE_1 | MCP9801_ALERT_LOW | \
+                     MCP9801_MODE_COMP | MCP9801_SHUTDOWN_OFF;
+    uint8_t buf[2] = { MCP9801_REG_CONFIG, config };
+    i2c_transmit(MCP9801_I2C_PERIPH, buf, sizeof(buf), MCP9801_I2C_ADDR, I2C_GENSTOP_YES);
+
+    /* Address device here */
+    uint8_t buf2[1] = {  MCP9801_REG_TEMP };
+    i2c_transmit(MCP9801_I2C_PERIPH, buf2, sizeof(buf2), MCP9801_I2C_ADDR, I2C_GENSTOP_NO);
+}
+
+int32_t mcp9801_read_mdegC()
+{
+    uint8_t rx[2];
+    i2c_receive(MCP9801_I2C_PERIPH, rx, sizeof(rx), MCP9801_I2C_ADDR);
+
+    /* Fixup endianness, sign-extend */
+    int32_t temp = (int16_t)((rx[0]<<8) | rx[1]);
+    return (temp * 1000) /256;
+}