Lee Kai Xuan
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Diff: targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c
- Revision:
- 0:f269e3021894
diff -r 000000000000 -r f269e3021894 targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,513 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 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 "i2c_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+
+#if DEVICE_I2C
+
+static const SWM_Map SWM_I2C_SDA[] = {
+ {7, 24},
+};
+
+static const SWM_Map SWM_I2C_SCL[] = {
+ {8, 0},
+};
+
+static uint8_t repeated_start = 0;
+
+#define I2C_DAT(x) (x->i2c->MSTDAT)
+#define I2C_STAT(x) ((x->i2c->STAT >> 1) & (0x07))
+
+static inline int i2c_status(i2c_t *obj) {
+ return I2C_STAT(obj);
+}
+
+// Wait until the Serial Interrupt (SI) is set
+static int i2c_wait_SI(i2c_t *obj) {
+ int timeout = 0;
+ while (!(obj->i2c->STAT & (1 << 0))) {
+ timeout++;
+ if (timeout > 100000) return -1;
+ }
+ return 0;
+}
+
+static inline void i2c_interface_enable(i2c_t *obj) {
+ obj->i2c->CFG |= (1 << 0);
+}
+
+static inline void i2c_power_enable(i2c_t *obj) {
+ LPC_SYSCON->SYSAHBCLKCTRL |= (1<<5);
+ LPC_SYSCON->PRESETCTRL &= ~(0x1<<6);
+ LPC_SYSCON->PRESETCTRL |= (0x1<<6);
+}
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
+ obj->i2c = (LPC_I2C_TypeDef *)LPC_I2C;
+
+ const SWM_Map *swm;
+ uint32_t regVal;
+
+ swm = &SWM_I2C_SDA[0];
+ regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+ LPC_SWM->PINASSIGN[swm->n] = regVal | (sda << swm->offset);
+
+ swm = &SWM_I2C_SCL[0];
+ regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+ LPC_SWM->PINASSIGN[swm->n] = regVal | (scl << swm->offset);
+
+ // enable power
+ i2c_power_enable(obj);
+ // set default frequency at 100k
+ i2c_frequency(obj, 100000);
+ i2c_interface_enable(obj);
+}
+
+//Actually Wrong. Spec says: First store Address in DAT before setting STA !
+//Undefined state when using single byte I2C operations and too much delay
+//between i2c_start and do_i2c_write(Address).
+//Also note that lpc812 will immediately continue reading a byte when Address b0 == 1
+inline int i2c_start(i2c_t *obj) {
+ int status = 0;
+ if (repeated_start) {
+ obj->i2c->MSTCTL = (1 << 1) | (1 << 0);
+ repeated_start = 0;
+ } else {
+ obj->i2c->MSTCTL = (1 << 1);
+ }
+ return status;
+}
+
+//Generate Stop condition and wait until bus is Idle
+//Will also send NAK for previous RD
+inline int i2c_stop(i2c_t *obj) {
+ int timeout = 0;
+
+ obj->i2c->MSTCTL = (1 << 2) | (1 << 0); // STP bit and Continue bit. Sends NAK to complete previous RD
+
+ //Spin until Ready (b0 == 1)and Status is Idle (b3..b1 == 000)
+ while ((obj->i2c->STAT & ((7 << 1) | (1 << 0))) != ((0 << 1) | (1 << 0))) {
+ timeout ++;
+ if (timeout > 100000) return 1;
+ }
+
+ return 0;
+}
+
+static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
+ // write the data
+ I2C_DAT(obj) = value;
+
+ if (!addr)
+ obj->i2c->MSTCTL = (1 << 0);
+
+ // wait and return status
+ i2c_wait_SI(obj);
+ return i2c_status(obj);
+}
+
+static inline int i2c_do_read(i2c_t *obj, int last) {
+ // wait for it to arrive
+ i2c_wait_SI(obj);
+ if (!last)
+ obj->i2c->MSTCTL = (1 << 0);
+
+ // return the data
+ return (I2C_DAT(obj) & 0xFF);
+}
+
+void i2c_frequency(i2c_t *obj, int hz) {
+ // No peripheral clock divider on the M0
+ uint32_t PCLK = SystemCoreClock;
+
+ uint32_t clkdiv = PCLK / (hz * 4) - 1;
+
+ obj->i2c->DIV = clkdiv;
+ obj->i2c->MSTTIME = 0;
+}
+
+// The I2C does a read or a write as a whole operation
+// There are two types of error conditions it can encounter
+// 1) it can not obtain the bus
+// 2) it gets error responses at part of the transmission
+//
+// We tackle them as follows:
+// 1) we retry until we get the bus. we could have a "timeout" if we can not get it
+// which basically turns it in to a 2)
+// 2) on error, we use the standard error mechanisms to report/debug
+//
+// Therefore an I2C transaction should always complete. If it doesn't it is usually
+// because something is setup wrong (e.g. wiring), and we don't need to programatically
+// check for that
+
+//New version WH, Tested OK for Start and Repeated Start
+//Old version was Wrong: Calls i2c_start without setting address, i2c_do_read continues before checking status, status check for wrong value
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
+ int count, status;
+
+ //Store the address+RD and then generate STA
+ I2C_DAT(obj) = address | 0x01;
+ i2c_start(obj);
+
+ // Wait for completion of STA and Sending of SlaveAddress+RD and first Read byte
+ i2c_wait_SI(obj);
+ status = i2c_status(obj);
+ if (status == 0x03) { // NAK on SlaveAddress
+ i2c_stop(obj);
+ return I2C_ERROR_NO_SLAVE;
+ }
+
+ // Read in all except last byte
+ for (count = 0; count < (length-1); count++) {
+
+ // Wait for it to arrive, note that first byte read after address+RD is already waiting
+ i2c_wait_SI(obj);
+ status = i2c_status(obj);
+ if (status != 0x01) { // RX RDY
+ i2c_stop(obj);
+ return count;
+ }
+ data[count] = I2C_DAT(obj) & 0xFF; // Store read byte
+
+ obj->i2c->MSTCTL = (1 << 0); // Send ACK and Continue to read
+ }
+
+ // Read final byte
+ // Wait for it to arrive
+ i2c_wait_SI(obj);
+
+ status = i2c_status(obj);
+ if (status != 0x01) { // RX RDY
+ i2c_stop(obj);
+ return count;
+ }
+ data[count] = I2C_DAT(obj) & 0xFF; // Store final read byte
+
+ // If not repeated start, send stop.
+ if (stop) {
+ i2c_stop(obj); // Also sends NAK for last read byte
+ } else {
+ repeated_start = 1;
+ }
+
+ return length;
+}
+
+
+
+//New version WH, Tested OK for Start and Repeated Start
+//Old version was Wrong: Calls i2c_start without setting address first
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
+ int i, status;
+
+ //Store the address+/WR and then generate STA
+ I2C_DAT(obj) = address & 0xFE;
+ i2c_start(obj);
+
+ // Wait for completion of STA and Sending of SlaveAddress+/WR
+ i2c_wait_SI(obj);
+ status = i2c_status(obj);
+ if (status == 0x03) { // NAK SlaveAddress
+ i2c_stop(obj);
+ return I2C_ERROR_NO_SLAVE;
+ }
+
+ //Write all bytes
+ for (i=0; i<length; i++) {
+ status = i2c_do_write(obj, data[i], 0);
+ if (status != 0x02) { // TX RDY. Handles a Slave NAK on datawrite
+ i2c_stop(obj);
+ return i;
+ }
+ }
+
+ // If not repeated start, send stop.
+ if (stop) {
+ i2c_stop(obj);
+ } else {
+ repeated_start = 1;
+ }
+
+ return length;
+}
+
+
+
+void i2c_reset(i2c_t *obj) {
+ i2c_stop(obj);
+}
+
+int i2c_byte_read(i2c_t *obj, int last) {
+ return (i2c_do_read(obj, last) & 0xFF);
+}
+
+int i2c_byte_write(i2c_t *obj, int data) {
+ int ack;
+ int status = i2c_do_write(obj, (data & 0xFF), 0);
+
+ switch(status) {
+ case 2:
+ ack = 1;
+ break;
+ default:
+ ack = 0;
+ break;
+ }
+
+ return ack;
+}
+
+#if DEVICE_I2CSLAVE
+
+#define I2C_SLVDAT(x) (x->i2c->SLVDAT)
+#define I2C_SLVSTAT(x) ((x->i2c->STAT >> 9) & (0x03))
+#define I2C_SLVSI(x) ((x->i2c->STAT >> 8) & (0x01))
+//#define I2C_SLVCNT(x) (x->i2c->SLVCTL = (1 << 0))
+//#define I2C_SLVNAK(x) (x->i2c->SLVCTL = (1 << 1))
+
+#if(0)
+// Wait until the Slave Serial Interrupt (SI) is set
+// Timeout when it takes too long.
+static int i2c_wait_slave_SI(i2c_t *obj) {
+ int timeout = 0;
+ while (!(obj->i2c->STAT & (1 << 8))) {
+ timeout++;
+ if (timeout > 100000) return -1;
+ }
+ return 0;
+}
+#endif
+
+void i2c_slave_mode(i2c_t *obj, int enable_slave) {
+
+ if (enable_slave) {
+// obj->i2c->CFG &= ~(1 << 0); //Disable Master mode
+ obj->i2c->CFG |= (1 << 1); //Enable Slave mode
+ }
+ else {
+// obj->i2c->CFG |= (1 << 0); //Enable Master mode
+ obj->i2c->CFG &= ~(1 << 1); //Disable Slave mode
+ }
+}
+
+// Wait for next I2C event and find out what is going on
+//
+int i2c_slave_receive(i2c_t *obj) {
+ int addr;
+
+ // Check if there is any data pending
+ if (! I2C_SLVSI(obj)) {
+ return 0; //NoData
+ };
+
+ // Check State
+ switch(I2C_SLVSTAT(obj)) {
+ case 0x0: // Slave address plus R/W received
+ // At least one of the four slave addresses has been matched by hardware.
+ // You can figure out which address by checking Slave address match Index in STAT register.
+
+ // Get the received address
+ addr = I2C_SLVDAT(obj) & 0xFF;
+ // Send ACK on address and Continue
+ obj->i2c->SLVCTL = (1 << 0);
+
+ if (addr == 0x00) {
+ return 2; //WriteGeneral
+ }
+ //check the RW bit
+ if ((addr & 0x01) == 0x01) {
+ return 1; //ReadAddressed
+ }
+ else {
+ return 3; //WriteAddressed
+ }
+ //break;
+
+ case 0x1: // Slave receive. Received data is available (Slave Receiver mode).
+ // Oops, should never get here...
+ obj->i2c->SLVCTL = (1 << 1); // Send NACK on received data, try to recover...
+ return 0; //NoData
+
+ case 0x2: // Slave transmit. Data can be transmitted (Slave Transmitter mode).
+ // Oops, should never get here...
+ I2C_SLVDAT(obj) = 0xFF; // Send dummy data for transmission
+ obj->i2c->SLVCTL = (1 << 0); // Continue and try to recover...
+ return 0; //NoData
+
+ case 0x3: // Reserved.
+ default: // Oops, should never get here...
+ obj->i2c->SLVCTL = (1 << 0); // Continue and try to recover...
+ return 0; //NoData
+ //break;
+ } //switch status
+}
+
+// The dedicated I2C Slave byte read and byte write functions need to be called
+// from 'common' mbed I2CSlave API for devices that have separate Master and
+// Slave engines such as the lpc812 and lpc1549.
+
+//Called when Slave is addressed for Write, Slave will receive Data in polling mode
+//Parameter last=1 means received byte will be NACKed.
+int i2c_slave_byte_read(i2c_t *obj, int last) {
+ int data;
+
+ // Wait for data
+ while (!I2C_SLVSI(obj)); // Wait forever
+//if (i2c_wait_slave_SI(obj) != 0) {return -2;} // Wait with timeout
+
+ // Dont bother to check State, were not returning it anyhow..
+//if (I2C_SLVSTAT(obj)) == 0x01) {
+ // Slave receive. Received data is available (Slave Receiver mode).
+//};
+
+ data = I2C_SLVDAT(obj) & 0xFF; // Get and store the received data
+ if (last) {
+ obj->i2c->SLVCTL = (1 << 1); // Send NACK on received data and Continue
+ }
+ else {
+ obj->i2c->SLVCTL = (1 << 0); // Send ACK on data and Continue to read
+ }
+
+ return data;
+}
+
+
+//Called when Slave is addressed for Read, Slave will send Data in polling mode
+//
+int i2c_slave_byte_write(i2c_t *obj, int data) {
+
+ // Wait until Ready
+ while (!I2C_SLVSI(obj)); // Wait forever
+// if (i2c_wait_slave_SI(obj) != 0) {return -2;} // Wait with timeout
+
+ // Check State
+ switch(I2C_SLVSTAT(obj)) {
+ case 0x0: // Slave address plus R/W received
+ // At least one of the four slave addresses has been matched by hardware.
+ // You can figure out which address by checking Slave address match Index in STAT register.
+ // I2C Restart occurred
+ return -1;
+ //break;
+ case 0x1: // Slave receive. Received data is available (Slave Receiver mode).
+ // Should not get here...
+ return -2;
+ //break;
+ case 0x2: // Slave transmit. Data can be transmitted (Slave Transmitter mode).
+ I2C_SLVDAT(obj) = data & 0xFF; // Store the data for transmission
+ obj->i2c->SLVCTL = (1 << 0); // Continue to send
+
+ return 1;
+ //break;
+ case 0x3: // Reserved.
+ default:
+ // Should not get here...
+ return -3;
+ //break;
+ } // switch status
+}
+
+
+//Called when Slave is addressed for Write, Slave will receive Data in polling mode
+//Parameter length (>=1) is the maximum allowable number of bytes. All bytes will be ACKed.
+int i2c_slave_read(i2c_t *obj, char *data, int length) {
+ int count=0;
+
+ // Read and ACK all expected bytes
+ while (count < length) {
+ // Wait for data
+ while (!I2C_SLVSI(obj)); // Wait forever
+// if (i2c_wait_slave_SI(obj) != 0) {return -2;} // Wait with timeout
+
+ // Check State
+ switch(I2C_SLVSTAT(obj)) {
+ case 0x0: // Slave address plus R/W received
+ // At least one of the four slave addresses has been matched by hardware.
+ // You can figure out which address by checking Slave address match Index in STAT register.
+ // I2C Restart occurred
+ return -1;
+ //break;
+
+ case 0x1: // Slave receive. Received data is available (Slave Receiver mode).
+ data[count] = I2C_SLVDAT(obj) & 0xFF; // Get and store the received data
+ obj->i2c->SLVCTL = (1 << 0); // Send ACK on data and Continue to read
+ break;
+
+ case 0x2: // Slave transmit. Data can be transmitted (Slave Transmitter mode).
+ case 0x3: // Reserved.
+ default: // Should never get here...
+ return -2;
+ //break;
+ } // switch status
+
+ count++;
+ } // for all bytes
+
+ return count; // Received the expected number of bytes
+}
+
+
+//Called when Slave is addressed for Read, Slave will send Data in polling mode
+//Parameter length (>=1) is the maximum number of bytes. Exit when Slave byte is NACKed.
+int i2c_slave_write(i2c_t *obj, const char *data, int length) {
+ int count;
+
+ // Send and all bytes or Exit on NAK
+ for (count=0; count < length; count++) {
+ // Wait until Ready for data
+ while (!I2C_SLVSI(obj)); // Wait forever
+// if (i2c_wait_slave_SI(obj) != 0) {return -2;} // Wait with timeout
+
+ // Check State
+ switch(I2C_SLVSTAT(obj)) {
+ case 0x0: // Slave address plus R/W received
+ // At least one of the four slave addresses has been matched by hardware.
+ // You can figure out which address by checking Slave address match Index in STAT register.
+ // I2C Restart occurred
+ return -1;
+ //break;
+ case 0x1: // Slave receive. Received data is available (Slave Receiver mode).
+ // Should not get here...
+ return -2;
+ //break;
+ case 0x2: // Slave transmit. Data can be transmitted (Slave Transmitter mode).
+ I2C_SLVDAT(obj) = data[count] & 0xFF; // Store the data for transmission
+ obj->i2c->SLVCTL = (1 << 0); // Continue to send
+ break;
+ case 0x3: // Reserved.
+ default:
+ // Should not get here...
+ return -3;
+ //break;
+ } // switch status
+ } // for all bytes
+
+ return length; // Transmitted the max number of bytes
+}
+
+
+// Set the four slave addresses.
+void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
+ obj->i2c->SLVADR0 = (address & 0xFE); // Store address in address 0 register
+ obj->i2c->SLVADR1 = (0x00 & 0xFE); // Store general call write address in address 1 register
+ obj->i2c->SLVADR2 = (0x01); // Disable address 2 register
+ obj->i2c->SLVADR3 = (0x01); // Disable address 3 register
+ obj->i2c->SLVQUAL0 = (mask & 0xFE); // Qualifier mask for address 0 register. Any maskbit that is 1 will always be a match
+}
+
+#endif
+
+#endif