Diff: targets/TARGET_ONSEMI/TARGET_NCS36510/ncs36510_i2c.c

Revision:

149:156823d33999

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+++ b/targets/TARGET_ONSEMI/TARGET_NCS36510/ncs36510_i2c.c	Fri Oct 28 11:17:30 2016 +0100
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+/**
+ ******************************************************************************
+ * @file i2c.c
+ * @brief I2C driver
+ * @internal
+ * @author ON Semiconductor
+ * $Rev:  $
+ * $Date: 2016-04-12 $
+ ******************************************************************************
+ * Copyright 2016 Semiconductor Components Industries LLC (d/b/a “ON Semiconductor”).
+ * All rights reserved.  This software and/or documentation is licensed by ON Semiconductor
+ * under limited terms and conditions.  The terms and conditions pertaining to the software
+ * and/or documentation are available at http://www.onsemi.com/site/pdf/ONSEMI_T&C.pdf
+ * (“ON Semiconductor Standard Terms and Conditions of Sale, Section 8 Software”) and
+ * if applicable the software license agreement.  Do not use this software and/or
+ * documentation unless you have carefully read and you agree to the limited terms and
+ * conditions.  By using this software and/or documentation, you agree to the limited
+ * terms and conditions.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
+ * OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
+ * ON SEMICONDUCTOR SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL,
+ * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
+ * @endinternal
+ *
+ * @ingroup i2c
+ *
+ * @details
+ *
+ * <h1> Reference document(s) </h1>
+ * <p>
+ * IPC7208 APB I2C Master Design Specification v1.3
+ * </p>
+ * The I2C bus is an industry-standard two-wire (clock and data) serial communication bus between master(initiator) and slave device.
+ * Within the procedure of the I2C-bus, unique situations arise which are defined as START and STOP conditions .A HIGH to LOW transition on
+ * the SDA line while SCL is HIGH is one such unique case. This situation indicates a START condition.A LOW to HIGH transition on the
+ * SDA line while SCL is HIGH defines a STOP condition.START and STOP conditions are always generated by the master. The bus is considered
+ * to be busy after the START condition. The bus is considered to be free again a certain time after the STOP condition.
+ * A master may start a transfer only if the bus is free. Two or more masters may generate a START condition.
+ * Every byte put on the SDA line must be 8-bits long.Each byte has to be followed by an acknowledge bit.
+ * This APB(Advanced peripheral bus) I2C Master is an APB Slave peripheral that can also serves as an I2C bus Master. The Command register
+ * is the programming interface to the I2C Engine. The commands arrive at the I2C Engine via the Command FIFO,so the first valid command
+ * that is written to the Command register is the first I2C instruction implemented on the I2C bus.Because the command interface provides
+ * the basic building blocks for any I2C transaction, access to a wide range of I2C slave devices is supported.
+ * I2C can be enabled by setting bit 7 of the control register .
+ * There is a generated clock (a divided version of the APB clock) in this module that may be used as the I2C System Clock.
+ * There are two FIFO in the I2C; Command FIFO and Read data FIFO
+ * The commands(I2C instructions) and data arrive at the I2C Engine via the Command FIFO.
+ * if the command FIFO is empty , up to 32 commands can be written to the command interface , it is programmer's responsibility to keep
+ * the track of command FIFO's status either by interrupt or by polling method by reading status register, which represents Operational
+ * Status of the I2C Module and its sub-modules.The action from the processor may be necessary after reading the status register.Reading
+ * the Status register clears the blkInt Interrupt signal.Read data FIFO is where data read by the processor from I2C slave is placed .
+ *
+ *
+ * <h1> Functional description (internal) </h1>
+ * <p>
+ *
+ * </p>
+ */
+#if DEVICE_I2C
+#include "i2c.h"
+
+/* See i2c.h for details */
+void fI2cInit(i2c_t *obj,PinName sda,PinName scl)
+{
+    uint32_t clockDivisor;
+    /* determine the I2C to use */
+    I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
+    I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
+    obj->membase = (I2cIpc7208Reg_pt)pinmap_merge(i2c_sda, i2c_scl);
+    MBED_ASSERT((int)obj->membase != NC);
+
+    /* By default disbale interrupts */
+    obj->membase->IER.WORD = False;
+
+    /* enable interrupt associated with the device */
+    if(obj->membase == I2C1REG) {
+        CLOCK_ENABLE(CLOCK_I2C);             /* enable i2c peripheral */
+        NVIC_ClearPendingIRQ(I2C_IRQn);
+        NVIC_EnableIRQ(I2C_IRQn);
+    } else {
+        CLOCK_ENABLE(CLOCK_I2C2);            /* enable i2c peripheral */
+        NVIC_ClearPendingIRQ(I2C2_IRQn);
+        NVIC_EnableIRQ(I2C2_IRQn);
+    }
+
+    /*select I2C clock source */
+    obj->membase->CR.BITS.I2C_CLK_SRC = True;
+
+    /* enable I2C clock divider */
+    obj->membase->CR.BITS.I2C_APB_CD_EN = True;
+
+    /* set default baud rate at 100k */
+    clockDivisor = ((fClockGetPeriphClockfrequency() / 100000) >> 2) - 2;
+    obj->membase->CR.BITS.CD_VAL = (clockDivisor & I2C_CLOCKDIVEDER_VAL_MASK);
+    obj->membase->PRE_SCALE_REG = (clockDivisor & I2C_APB_CLK_DIVIDER_VAL_MASK) >> 5; /**< Zero pre-scale value not allowed */
+
+    /* Cross bar setting */
+    pinmap_pinout(sda, PinMap_I2C_SDA);
+    pinmap_pinout(scl, PinMap_I2C_SCL);
+
+    /*Enable open drain & pull up for sda & scl pin */
+    pin_mode(sda, OpenDrainPullUp);
+    pin_mode(scl, OpenDrainPullUp);
+
+    /* PAD drive strength */
+    PadReg_t *padRegSda = (PadReg_t*)(PADREG_BASE + (sda * PAD_REG_ADRS_BYTE_SIZE));
+    PadReg_t *padRegScl = (PadReg_t*)(PADREG_BASE + (scl * PAD_REG_ADRS_BYTE_SIZE));
+
+    CLOCK_ENABLE(CLOCK_PAD);
+    padRegSda->PADIO0.BITS.POWER = 1; /* sda: Drive strength */
+    padRegScl->PADIO0.BITS.POWER = 1; /* scl: Drive strength */
+    CLOCK_DISABLE(CLOCK_PAD);
+
+    CLOCK_ENABLE(CLOCK_GPIO);
+    GPIOREG->W_OUT |= ((True << sda) | (True << scl));
+    CLOCK_DISABLE(CLOCK_GPIO);
+
+    /* Enable i2c module */
+    obj->membase->CR.BITS.I2C_MODULE_EN = True;
+}
+
+/* See i2c.h for details */
+void fI2cFrequency(i2c_t *obj, uint32_t hz)
+{
+    /* Set user baud rate */
+    uint32_t clockDivisor;
+    clockDivisor = ((fClockGetPeriphClockfrequency() / hz) >> 2) - 2;
+    obj->membase->CR.BITS.CD_VAL = (clockDivisor & I2C_CLOCKDIVEDER_VAL_MASK);
+    obj->membase->PRE_SCALE_REG = (clockDivisor & I2C_APB_CLK_DIVIDER_VAL_MASK) >> 5; /**< Zero pre-scale value not allowed */
+}
+
+/* See i2c.h for details */
+int32_t fI2cStart(i2c_t *obj)
+{
+    /* Send start bit */
+    obj->membase->CMD_REG = I2C_CMD_START;
+    return I2C_API_STATUS_SUCCESS;
+}
+
+/* See i2c.h for details */
+int32_t fI2cStop(i2c_t *obj)
+{
+    /* Send stop bit */
+    obj->membase->CMD_REG = I2C_CMD_STOP;
+    if (obj->membase->STATUS.WORD & (I2C_STATUS_CMD_FIFO_FULL_BIT |
+                                     I2C_STATUS_CMD_FIFO_OFL_BIT |
+                                     I2C_STATUS_BUS_ERR_BIT)) {
+        /* I2c error occured */
+        return I2C_ERROR_BUS_BUSY;
+    }
+    return I2C_API_STATUS_SUCCESS;
+}
+
+/* See i2c.h for details */
+int32_t fI2cReadB(i2c_t *d, char *buf, int len)
+{
+    int32_t read = 0;
+
+    while (read < len) {
+        /* Send read command */
+        d->membase->CMD_REG = I2C_CMD_RDAT8;
+        while(!RD_DATA_READY) {
+            if (I2C_BUS_ERR_CHECK) {
+                /* Bus error occured */
+                return I2C_ERROR_BUS_BUSY;
+            }
+        }
+        buf[read++] = d->membase->RD_FIFO_REG; /**< Reading 'read FIFO register' will clear status register */
+
+        if(!(read>=len)) {  /* No ACK will be generated for the last read, upper level I2C protocol should generate */
+            d->membase->CMD_REG=I2C_CMD_WDAT0; /* TODO based on requirement generate ACK or NACK Based on the requirement. */
+        }
+
+        /* check for FIFO underflow */
+        if(I2C_UFL_CHECK) {
+            return I2C_ERROR_NO_SLAVE; /* TODO No error available for this in i2c_api.h */
+        }
+        if(I2C_BUS_ERR_CHECK) {
+            /* Bus error */
+            return I2C_ERROR_BUS_BUSY;
+        }
+    }
+
+    return read;
+}
+
+/* See i2c.h for details */
+int32_t fI2cWriteB(i2c_t *d, const char *buf, int len)
+{
+    int32_t write = 0;
+
+    while (write < len) {
+        /* Send write command */
+        d->membase->CMD_REG = I2C_CMD_WDAT8;
+        if(buf[write] == I2C_CMD_RDAT8) {
+            /* SW work around to counter FSM issue. If the only command in the CMD FIFO is the WDAT8 command (data of 0x13)
+            then as the command is read out (i.e. the FIFO goes empty), the WDAT8 command will be misinterpreted as a
+            RDAT8 command by the data FSM; resulting in an I2C bus error (NACK instead of an ACK). */
+            /* Send 0x13 bit wise */
+            d->membase->CMD_REG = I2C_CMD_WDAT0;
+            d->membase->CMD_REG = I2C_CMD_WDAT0;
+            d->membase->CMD_REG = I2C_CMD_WDAT0;
+            d->membase->CMD_REG = I2C_CMD_WDAT1;
+
+            d->membase->CMD_REG = I2C_CMD_WDAT0;
+            d->membase->CMD_REG = I2C_CMD_WDAT0;
+            d->membase->CMD_REG = I2C_CMD_WDAT1;
+            d->membase->CMD_REG = I2C_CMD_WDAT1;
+        } else {
+            /* Send data */
+            d->membase->CMD_REG = buf[write++];
+        }
+        d->membase->CMD_REG = I2C_CMD_VRFY_ACK; /* TODO Verify ACK based on requirement, Do we need? */
+
+        while(FIFO_OFL_CHECK); /* Wait till command overflow ends */
+
+        if (I2C_BUS_ERR_CHECK) {
+            /* Bus error */
+            return I2C_ERROR_BUS_BUSY;
+        }
+    }
+
+    return write;
+}
+
+#endif /* DEVICE_I2C */