Diff: targets/hal/TARGET_Freescale/TARGET_K20XX/i2c_api.c

Revision:

445:3312ed629f01

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_Freescale/TARGET_K20XX/i2c_api.c	Thu Jan 15 19:30:07 2015 +0000
@@ -0,0 +1,378 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed_assert.h"
+#include "i2c_api.h"
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "clk_freqs.h"
+#include "PeripheralPins.h"
+
+static const uint16_t ICR[0x40] = {
+      20,   22,   24,   26,   28,
+      30,   34,   40,   28,   32,
+      36,   40,   44,   48,   56,
+      68,   48,   56,   64,   72,
+      80,   88,  104,  128,   80,
+      96,  112,  128,  144,  160,
+      192,  240,  160,  192,  224,
+      256,  288,  320,  384,  480,
+      320,  384,  448,  512,  576,
+      640,  768,  960,  640,  768,
+      896, 1024, 1152, 1280, 1536,
+      1920, 1280, 1536, 1792, 2048,
+      2304, 2560, 3072, 3840
+};
+
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
+    // 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->i2c = (I2C_Type*)pinmap_merge(i2c_sda, i2c_scl);
+    MBED_ASSERT((int)obj->i2c != NC);    
+    
+#if defined(TARGET_K20DX256)
+    switch ((int)obj->i2c) {
+        case I2C_0: SIM->SCGC4 |= SIM_SCGC4_I2C0_MASK;
+        case I2C_1: SIM->SCGC4 |= SIM_SCGC4_I2C1_MASK;               
+    }
+#else
+    SIM->SCGC4 |= SIM_SCGC4_I2C0_MASK;    		
+#endif    
+
+    // set default frequency at 100k
+    i2c_frequency(obj, 100000);
+
+    // enable I2C interface
+    obj->i2c->C1 |= 0x80;
+
+    pinmap_pinout(sda, PinMap_I2C_SDA);
+    pinmap_pinout(scl, PinMap_I2C_SCL);
+    /* enable open drain for I2C pins, only port b available */
+    uint32_t pin_n  = (uint32_t)(sda & 0x7C) >> 2;
+    PORTB->PCR[pin_n] |= PORT_PCR_ODE_MASK;
+    pin_n  = (uint32_t)(scl & 0x7C) >> 2;
+    PORTB->PCR[pin_n] |= PORT_PCR_ODE_MASK;
+}
+
+int i2c_start(i2c_t *obj) {
+    // if we are in the middle of a transaction
+    // activate the repeat_start flag
+    if (obj->i2c->S & I2C_S_BUSY_MASK) {
+        obj->i2c->C1 |= 0x04;
+    } else {
+        obj->i2c->C1 |= I2C_C1_MST_MASK;
+        obj->i2c->C1 |= I2C_C1_TX_MASK;
+    }
+    return 0;
+}
+
+int i2c_stop(i2c_t *obj) {
+    volatile uint32_t n = 0;
+    obj->i2c->C1 &= ~I2C_C1_MST_MASK;
+    obj->i2c->C1 &= ~I2C_C1_TX_MASK;
+
+    // It seems that there are timing problems
+    // when there is no waiting time after a STOP.
+    // This wait is also included on the samples
+    // code provided with the freedom board
+    for (n = 0; n < 100; n++)
+        __NOP();
+    return 0;
+}
+
+static int timeout_status_poll(i2c_t *obj, uint32_t mask) {
+    uint32_t i, timeout = 100000;
+
+    for (i = 0; i < timeout; i++) {
+        if (obj->i2c->S & mask)
+            return 0;
+    }
+
+    return 1;
+}
+
+// this function waits the end of a tx transfer and return the status of the transaction:
+//    0: OK ack received
+//    1: OK ack not received
+//    2: failure
+static int i2c_wait_end_tx_transfer(i2c_t *obj) {
+
+    // wait for the interrupt flag
+    if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) {
+        return 2;
+    }
+
+    obj->i2c->S |= I2C_S_IICIF_MASK;
+
+    // wait transfer complete
+    if (timeout_status_poll(obj, I2C_S_TCF_MASK)) {
+        return 2;
+    }
+
+    // check if we received the ACK or not
+    return obj->i2c->S & I2C_S_RXAK_MASK ? 1 : 0;
+}
+
+// this function waits the end of a rx transfer and return the status of the transaction:
+//    0: OK
+//    1: failure
+static int i2c_wait_end_rx_transfer(i2c_t *obj) {
+    // wait for the end of the rx transfer
+    if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) {
+        return 1;
+    }
+
+    obj->i2c->S |= I2C_S_IICIF_MASK;
+
+    return 0;
+}
+
+static void i2c_send_nack(i2c_t *obj) {
+    obj->i2c->C1 |= I2C_C1_TXAK_MASK; // NACK
+}
+
+static void i2c_send_ack(i2c_t *obj) {
+    obj->i2c->C1 &= ~I2C_C1_TXAK_MASK; // ACK
+}
+
+static int i2c_do_write(i2c_t *obj, int value) {
+    // write the data
+    obj->i2c->D = value;
+
+    // init and wait the end of the transfer
+    return i2c_wait_end_tx_transfer(obj);
+}
+
+static int i2c_do_read(i2c_t *obj, char * data, int last) {
+    if (last) {
+        i2c_send_nack(obj);
+    } else {
+        i2c_send_ack(obj);
+    }
+
+    *data = (obj->i2c->D & 0xFF);
+
+    // start rx transfer and wait the end of the transfer
+    return i2c_wait_end_rx_transfer(obj);
+}
+
+void i2c_frequency(i2c_t *obj, int hz) {
+    uint8_t icr = 0;
+    uint8_t mult = 0;
+    uint32_t error = 0;
+    uint32_t p_error = 0xffffffff;
+    uint32_t ref = 0;
+    uint8_t i, j;
+    // bus clk
+    uint32_t PCLK = bus_frequency();
+    uint32_t pulse = PCLK / (hz * 2);
+
+    // we look for the values that minimize the error
+
+    // test all the MULT values
+    for (i = 1; i < 5; i*=2) {
+        for (j = 0; j < 0x40; j++) {
+            ref = PCLK / (i*ICR[j]);
+            if (ref > (uint32_t)hz)
+                continue;
+            error = hz - ref;
+            if (error < p_error) {
+                icr = j;
+                mult = i/2;
+                p_error = error;
+            }
+        }
+    }
+    pulse = icr | (mult << 6);
+
+    // I2C Rate
+    obj->i2c->F = pulse;
+}
+
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
+    int count;
+    char dummy_read, *ptr;
+
+    if (i2c_start(obj)) {
+        i2c_stop(obj);
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    if (i2c_do_write(obj, (address | 0x01))) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+
+    // set rx mode
+    obj->i2c->C1 &= ~I2C_C1_TX_MASK;
+
+    // Read in bytes
+    for (count = 0; count < (length); count++) {
+        ptr = (count == 0) ? &dummy_read : &data[count - 1];
+        uint8_t stop_ = (count == (length - 1)) ? 1 : 0;
+        if (i2c_do_read(obj, ptr, stop_)) {
+            i2c_stop(obj);
+            return count;
+        }
+    }
+
+    // If not repeated start, send stop.
+    if (stop)
+        i2c_stop(obj);
+
+    // last read
+    data[count-1] = obj->i2c->D;
+
+    return length;
+}
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
+    int i;
+
+    if (i2c_start(obj)) {
+        i2c_stop(obj);
+        return I2C_ERROR_BUS_BUSY;
+    }
+
+    if (i2c_do_write(obj, (address & 0xFE))) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+
+    for (i = 0; i < length; i++) {
+        if(i2c_do_write(obj, data[i])) {
+            i2c_stop(obj);
+            return i;
+        }
+    }
+
+    if (stop)
+        i2c_stop(obj);
+
+    return length;
+}
+
+void i2c_reset(i2c_t *obj) {
+    i2c_stop(obj);
+}
+
+int i2c_byte_read(i2c_t *obj, int last) {
+    char data;
+    
+    // set rx mode
+    obj->i2c->C1 &= ~I2C_C1_TX_MASK;
+    
+    // Setup read
+    i2c_do_read(obj, &data, last);
+
+    // set tx mode
+    obj->i2c->C1 |= I2C_C1_TX_MASK;
+    return obj->i2c->D;
+}
+
+int i2c_byte_write(i2c_t *obj, int data) {
+    // set tx mode
+    obj->i2c->C1 |= I2C_C1_TX_MASK;
+
+    return !i2c_do_write(obj, (data & 0xFF));
+}
+
+
+#if DEVICE_I2CSLAVE
+void i2c_slave_mode(i2c_t *obj, int enable_slave) {
+    if (enable_slave) {
+        // set slave mode
+        obj->i2c->C1 &= ~I2C_C1_MST_MASK;
+        obj->i2c->C1 |= I2C_C1_IICIE_MASK;
+    } else {
+        // set master mode
+        obj->i2c->C1 |= I2C_C1_MST_MASK;
+    }
+}
+
+int i2c_slave_receive(i2c_t *obj) {
+    switch(obj->i2c->S) {
+        // read addressed
+        case 0xE6:
+            return 1;
+        // write addressed
+        case 0xE2:
+            return 3;
+        default:
+            return 0;
+    }
+}
+
+int i2c_slave_read(i2c_t *obj, char *data, int length) {
+    uint8_t dummy_read;
+    uint8_t * ptr;
+    int count;
+
+    // set rx mode
+    obj->i2c->C1 &= ~I2C_C1_TX_MASK;
+
+    // first dummy read
+    dummy_read = obj->i2c->D;
+    if (i2c_wait_end_rx_transfer(obj))
+        return 0;
+
+    // read address
+    dummy_read = obj->i2c->D;
+    if (i2c_wait_end_rx_transfer(obj))
+        return 0;
+
+    // read (length - 1) bytes
+    for (count = 0; count < (length - 1); count++) {
+        data[count] = obj->i2c->D;
+        if (i2c_wait_end_rx_transfer(obj))
+            return count;
+    }
+
+    // read last byte
+    ptr = (length == 0) ? &dummy_read : (uint8_t *)&data[count];
+    *ptr = obj->i2c->D;
+
+    return (length) ? (count + 1) : 0;
+}
+
+int i2c_slave_write(i2c_t *obj, const char *data, int length) {
+    int i, count = 0;
+
+    // set tx mode
+    obj->i2c->C1 |= I2C_C1_TX_MASK;
+
+    for (i = 0; i < length; i++) {
+        if (i2c_do_write(obj, data[count++]) == 2)
+            return i;
+    }
+
+    // set rx mode
+    obj->i2c->C1 &= ~I2C_C1_TX_MASK;
+
+    // dummy rx transfer needed
+    // otherwise the master cannot generate a stop bit
+    obj->i2c->D;
+    if (i2c_wait_end_rx_transfer(obj) == 2)
+        return count;
+
+    return count;
+}
+
+void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
+    obj->i2c->A1 = address & 0xfe;
+}
+#endif