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authorJosh Blum <josh@joshknows.com>2010-02-10 11:57:58 -0800
committerJosh Blum <josh@joshknows.com>2010-02-10 11:57:58 -0800
commitd088a11bf7c257ba45bf0c37a41e5038b302bc44 (patch)
tree8bbb4d90285a181c603c117de4504e73066afe48 /firmware/microblaze/lib/i2c.c
parente2044e13ec4ad94e9739402257134abd92cf1521 (diff)
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Copied a snapshot of the usrp2 firmware into the microblaze firmware directory in the uhd repo.
Added erllc copyrights to the files created and modified at erllc.
Diffstat (limited to 'firmware/microblaze/lib/i2c.c')
-rw-r--r--firmware/microblaze/lib/i2c.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/firmware/microblaze/lib/i2c.c b/firmware/microblaze/lib/i2c.c
new file mode 100644
index 000000000..3f738733b
--- /dev/null
+++ b/firmware/microblaze/lib/i2c.c
@@ -0,0 +1,127 @@
+/* -*- c -*- */
+/*
+ * Copyright 2007 Free Software Foundation, Inc.
+ *
+ * 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 "i2c.h"
+#include "memory_map.h"
+#include "stdint.h"
+
+#define MAX_WB_DIV 4 // maximum wishbone divisor (from 100 MHz MASTER_CLK)
+
+// prescaler divisor values for 100 kHz I2C [uses 5 * SCLK internally]
+
+#define PRESCALER(wb_div) (((MASTER_CLK_RATE/(wb_div)) / (5 * 100000)) - 1)
+
+static uint16_t prescaler_values[MAX_WB_DIV+1] = {
+ 0xffff, // 0: can't happen
+ PRESCALER(1), // 1: 100 MHz
+ PRESCALER(2), // 2: 50 MHz
+ PRESCALER(3), // 3: 33.333 MHz
+ PRESCALER(4), // 4: 25 MHz
+};
+
+void
+i2c_init(void)
+{
+ i2c_regs->ctrl = 0; // disable core
+
+ // setup prescaler depending on wishbone divisor
+ int wb_div = hwconfig_wishbone_divisor();
+ if (wb_div > MAX_WB_DIV)
+ wb_div = MAX_WB_DIV;
+
+ i2c_regs->prescaler_lo = prescaler_values[wb_div] & 0xff;
+ i2c_regs->prescaler_hi = (prescaler_values[wb_div] >> 8) & 0xff;
+
+ i2c_regs->ctrl = I2C_CTRL_EN; // enable core
+
+ // FIXME interrupt driven?
+}
+
+static inline void
+wait_for_xfer(void)
+{
+ while (i2c_regs->cmd_status & I2C_ST_TIP) // wait for xfer to complete
+ ;
+}
+
+static inline bool
+wait_chk_ack(void)
+{
+ wait_for_xfer();
+
+ if ((i2c_regs->cmd_status & I2C_ST_RXACK) != 0){ // target NAK'd
+ return false;
+ }
+ return true;
+}
+
+bool
+i2c_read (unsigned char i2c_addr, unsigned char *buf, unsigned int len)
+{
+ if (len == 0) // reading zero bytes always works
+ return true;
+
+ while (i2c_regs->cmd_status & I2C_ST_BUSY)
+ ;
+
+ i2c_regs->data = (i2c_addr << 1) | 1; // 7 bit address and read bit (1)
+ // generate START and write addr
+ i2c_regs->cmd_status = I2C_CMD_WR | I2C_CMD_START;
+ if (!wait_chk_ack())
+ goto fail;
+
+ for (; len > 0; buf++, len--){
+ i2c_regs->cmd_status = I2C_CMD_RD | (len == 1 ? (I2C_CMD_NACK | I2C_CMD_STOP) : 0);
+ wait_for_xfer();
+ *buf = i2c_regs->data;
+ }
+ return true;
+
+ fail:
+ i2c_regs->cmd_status = I2C_CMD_STOP; // generate STOP
+ return false;
+}
+
+
+bool
+i2c_write(unsigned char i2c_addr, const unsigned char *buf, unsigned int len)
+{
+ while (i2c_regs->cmd_status & I2C_ST_BUSY)
+ ;
+
+ i2c_regs->data = (i2c_addr << 1) | 0; // 7 bit address and write bit (0)
+
+ // generate START and write addr (and maybe STOP)
+ i2c_regs->cmd_status = I2C_CMD_WR | I2C_CMD_START | (len == 0 ? I2C_CMD_STOP : 0);
+ if (!wait_chk_ack())
+ goto fail;
+
+ for (; len > 0; buf++, len--){
+ i2c_regs->data = *buf;
+ i2c_regs->cmd_status = I2C_CMD_WR | (len == 1 ? I2C_CMD_STOP : 0);
+ if (!wait_chk_ack())
+ goto fail;
+ }
+ return true;
+
+ fail:
+ i2c_regs->cmd_status = I2C_CMD_STOP; // generate STOP
+ return false;
+}
+
+