Mouse code for the MacroRat
Diff: mbed-dev/targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c
- Revision:
- 18:6a4db94011d3
diff -r f713758f6238 -r 6a4db94011d3 mbed-dev/targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-dev/targets/TARGET_NXP/TARGET_LPC81X/i2c_api.c Sun May 14 23:18:57 2017 +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