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authorMichael Ossmann2012-06-04 17:57:49 -0600
committerMichael Ossmann2012-06-04 17:57:49 -0600
commite7941eace9a5a782c457bb4163e44360dd3eb900 (patch)
treeae223f93e562bd5d9d7612438c5bbd3fafb069ba
parent569801687744d5f4f4157ea186a8a6c1d159d285 (diff)
added i2c.c that I forgot earlier
-rw-r--r--lib/lpc43xx/i2c.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/lib/lpc43xx/i2c.c b/lib/lpc43xx/i2c.c
new file mode 100644
index 0000000..9d742e0
--- /dev/null
+++ b/lib/lpc43xx/i2c.c
@@ -0,0 +1,94 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2012 Michael Ossmann <mike@ossmann.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This is a very minimal I2C driver just to make sure we can get the
+ * peripheral working.
+ */
+
+#include <libopencm3/lpc43xx/i2c.h>
+#include <libopencm3/lpc43xx/scu.h>
+#include <libopencm3/lpc43xx/cgu.h>
+
+void i2c0_init(void)
+{
+ /* enable input on SCL and SDA pins */
+ SCU_SFSI2C0 = SCU_I2C0_NOMINAL;
+
+ /* use PLL1 as clock source for APB1 (including I2C0) */
+ CGU_BASE_APB1_CLK = (CGU_SRC_PLL1 << CGU_BASE_CLK_SEL_SHIFT);
+
+ /* FIXME assuming we're on IRC at 96 MHz */
+
+ /* 400 kHz I2C */
+ /*
+ I2C0_SCLH = 120;
+ I2C0_SCLL = 120;
+ */
+
+ /* 100 kHz I2C */
+ I2C0_SCLH = 480;
+ I2C0_SCLL = 480;
+ /* FIXME not sure why this appears to run at about 290 kHz */
+
+ /* clear the control bits */
+ I2C0_CONCLR = (I2C_CONCLR_AAC | I2C_CONCLR_SIC
+ | I2C_CONCLR_STAC | I2C_CONCLR_I2ENC);
+
+ /* enable I2C0 */
+ I2C0_CONSET = I2C_CONSET_I2EN;
+}
+
+/* transmit start bit */
+void i2c0_tx_start(void)
+{
+ I2C0_CONCLR = I2C_CONCLR_SIC;
+ I2C0_CONSET = I2C_CONSET_STA;
+ while (!(I2C0_CONSET & I2C_CONSET_SI));
+ I2C0_CONCLR = I2C_CONCLR_STAC;
+}
+
+/* transmit data byte */
+void i2c0_tx_byte(u8 byte)
+{
+ if (I2C0_CONSET & I2C_CONSET_STA)
+ I2C0_CONCLR = I2C_CONCLR_STAC;
+ I2C0_DAT = byte;
+ I2C0_CONCLR = I2C_CONCLR_SIC;
+ while (!(I2C0_CONSET & I2C_CONSET_SI));
+}
+
+/* receive data byte */
+u8 i2c0_rx_byte(void)
+{
+ if (I2C0_CONSET & I2C_CONSET_STA)
+ I2C0_CONCLR = I2C_CONCLR_STAC;
+ I2C0_CONCLR = I2C_CONCLR_SIC;
+ while (!(I2C0_CONSET & I2C_CONSET_SI));
+ return I2C0_DAT;
+}
+
+/* transmit stop bit */
+void i2c0_stop(void)
+{
+ if (I2C0_CONSET & I2C_CONSET_STA)
+ I2C0_CONCLR = I2C_CONCLR_STAC;
+ I2C0_CONSET = I2C_CONSET_STO;
+ I2C0_CONCLR = I2C_CONCLR_SIC;
+}