diff options
| -rw-r--r-- | CREDITS | 6 | ||||
| -rw-r--r-- | examples/i2c_slave_example.cpp | 110 | ||||
| -rw-r--r-- | libmaple/i2c.c | 271 | ||||
| -rw-r--r-- | libmaple/include/libmaple/i2c.h | 62 | ||||
| -rw-r--r-- | libmaple/include/libmaple/i2c_common.h | 14 |
5 files changed, 460 insertions, 3 deletions
@@ -18,6 +18,11 @@ E: mbolivar@leaflabs.com D: Current libmaple maintainer D: Random libmaple hacks +N: Barry Carter ("ginge") +E: barry.carter@gmail.com +D: Added I2C slave support +W: headfuzz.co.uk + N: Anton Eltchaninov E: anton.eltchaninov@gmail.com D: STM32F1 value line support @@ -81,3 +86,4 @@ W: http://sarup.dk/index.html N: Andy Scott ("xttocs") E: andy.g.scott@gmail.com D: LiquidCrystal library + diff --git a/examples/i2c_slave_example.cpp b/examples/i2c_slave_example.cpp new file mode 100644 index 0000000..98da58c --- /dev/null +++ b/examples/i2c_slave_example.cpp @@ -0,0 +1,110 @@ +/* + * i2c_slave example.cpp + * + * Created on: 4 Sep 2012 + * Author: Barry Carter <barry.carter@gmail.com> + */ +#include <wirish/wirish.h> +#include <i2c.h> + +#define USE_BUFFERED_EXAMPLE 1 + +i2c_msg msg; +i2c_msg *pmsg = &msg; +uint8 buffer[255]; + +uint8 value_to_print = 'A'; + +void funcrx(i2c_msg *msg) +{ + // Received length will be in msg->length + char return_data = msg->data[0]; + value_to_print = return_data; +} + +#if USE_BUFFERED_EXAMPLE == 1 +/* We ARE using a buffer to transmit the data out. + * Make sure you fill the buffer with the data AND you set the length correctly + */ +void functx(i2c_msg *msg) +{ + // Cheeky. We are using the received byte of the data which is currently in + // byte 0 to echo it back to the master device + //msg->data[0] = 0x01; // We are re-using the rx buffer here to echo the request back + msg->data[1] = 0x02; + msg->data[2] = 0x03; + msg->data[3] = 0x04; + msg->data[4] = 0x05; + msg->length = 5; +} + +#else + +/* We are NOT using the buffered data transmission + * We will get this callback for each outgoing packet. Make sure to call i2c_write + * Strickly speaking, we should be sending a NACk on the last byte we want to send + * but for this test example I am going to assume the master will NACK it when it + * wants to stop. + */ +void functx(i2c_msg *msg) +{ + i2c_write(I2C1, msg->data[0]); +} + +#endif + + +void setup() { + SerialUSB.begin(); + SerialUSB.println("I2C Slave example"); + + // attach the buffer + msg.data = buffer; + + /* Init slave mode. Enables master too + * We are going to configure the slave device to + * - enable fast I2C (400khz) + * - dual addresses (can have 2 addresses per module) + * general call (accepts data writes to 0x00 on a broadcast basis) + * + * If the buffered example is enabled, then we also enable the + * buffer for rx and tx. + * Note you can independently enable/disable RX and TX buffers to + * allow a buffered read and direct writes. Useful if you don't know how + * much the master will read. + */ +#if USE_BUFFERED_EXAMPLE == 1 + i2c_slave_enable(I2C1, I2C_FAST_MODE | I2C_SLAVE_DUAL_ADDRESS | I2C_SLAVE_GENERAL_CALL | I2C_SLAVE_USE_RX_BUFFER | I2C_SLAVE_USE_TX_BUFFER); +#else + i2c_slave_enable(I2C1, I2C_FAST_MODE | I2C_SLAVE_DUAL_ADDRESS | I2C_SLAVE_GENERAL_CALL); +#endif + + // attach receive handler + i2c_slave_attach_recv_handler(I2C1, &msg, funcrx); + // attach transmit handler + i2c_slave_attach_transmit_handler(I2C1, &msg, functx); + + // set addresss 1 to 16 + i2c_slave_set_own_address(I2C1, 0x10); + // set addresss 2 to 32 + i2c_slave_set_own_address2(I2C1, 0x20); +} + +void loop() { + SerialUSB.print("Last byte: "); + SerialUSB.println(value_to_print); +} + +// Force init() to be called before anything else. +__attribute__((constructor)) void premain() { + init(); +} + +int main(void) { + setup(); + + while (true) { + loop(); + } + return 0; +} diff --git a/libmaple/i2c.c b/libmaple/i2c.c index 9c93d3f..bbbf123 100644 --- a/libmaple/i2c.c +++ b/libmaple/i2c.c @@ -28,9 +28,11 @@ /** * @file libmaple/i2c.c * @author Perry Hung <perry@leaflabs.com> + * @author Barry Carter <barry.carter@gmail.com> * @brief Inter-Integrated Circuit (I2C) support. * - * Currently, only master mode is supported. + * Master and Slave supported + * Slave code added Barry Carter 2012 */ #include "i2c_private.h" @@ -154,6 +156,7 @@ void i2c_bus_reset(const i2c_dev *dev) { void i2c_init(i2c_dev *dev) { rcc_reset_dev(dev->clk_id); rcc_clk_enable(dev->clk_id); + _i2c_irq_priority_fixup(dev); } /* Hack for deprecated bit of STM32F1 functionality */ @@ -198,13 +201,51 @@ void i2c_master_enable(i2c_dev *dev, uint32 flags) { nvic_irq_enable(dev->er_nvic_line); i2c_enable_irq(dev, I2C_IRQ_EVENT | I2C_IRQ_BUFFER | I2C_IRQ_ERROR); + /* Configure the slave unit */ + if (flags & I2C_SLAVE_DUAL_ADDRESS) { + i2c_slave_dual_address_enable(dev); + } + + if (flags & I2C_SLAVE_GENERAL_CALL) { + i2c_slave_general_call_enable(dev); + } + + /* store all of the flags */ + dev->config_flags = flags; + /* Make it go! */ i2c_peripheral_enable(dev); + i2c_enable_ack(dev); dev->state = I2C_STATE_IDLE; } /** + * @brief Initialize an I2C device as slave (and master) + * @param dev Device to enable + * @param flags Bitwise or of the following I2C options: + * I2C_FAST_MODE: 400 khz operation, + * I2C_DUTY_16_9: 16/9 Tlow/Thigh duty cycle (only applicable for + * fast mode), + * I2C_BUS_RESET: Reset the bus and clock out any hung slaves on + * initialization, + * I2C_10BIT_ADDRESSING: Enable 10-bit addressing, + * I2C_REMAP: (deprecated, STM32F1 only) Remap I2C1 to SCL/PB8 + * SDA/PB9. + * I2C_SLAVE_DUAL_ADDRESS: Slave can respond on 2 i2C addresses + * I2C_SLAVE_GENERAL_CALL: SLA+W broadcast to all general call + * listeners on bus. Addr 0x00 + * I2C_SLAVE_USE_RX_BUFFER: Use a buffer to receive the incoming + * data. Callback at end of recv + * I2C_SLAVE_USE_TX_BUFFER: Use a buffer to transmit data. + * Callback will be called before tx + */ +void i2c_slave_enable(i2c_dev *dev, uint32 flags) { + i2c_disable(dev); + i2c_master_enable(dev, dev->config_flags | flags); +} + +/** * @brief Process an i2c transaction. * * Transactions are composed of one or more i2c_msg's, and may be read @@ -304,6 +345,164 @@ void _i2c_irq_handler(i2c_dev *dev) { dev->timestamp = systick_uptime(); /* + * Add Slave support + */ + + /* Check to see if MSL master slave bit is set */ + if ((sr2 & I2C_SR2_MSL) != I2C_SR2_MSL) { /* 0 = slave mode 1 = master */ + + /* Check for address match */ + if (sr1 & I2C_SR1_ADDR) { + /* Find out which address was matched */ + /* Check the general call address first */ + if (sr2 & I2C_SR2_GENCALL) { + dev->i2c_slave_msg->addr = 0; + } + /* We matched the secondary address */ + else if (sr2 & I2C_SR2_DUALF) { + dev->i2c_slave_msg->addr = dev->regs->OAR2 & 0xFE; + } + /* We matched the primary address */ + else if ((sr2 & I2C_SR2_DUALF) != I2C_SR2_DUALF) { + dev->i2c_slave_msg->addr = dev->regs->OAR1 & 0xFE; + } + /* Shouldn't get here */ + else { + dev->i2c_slave_msg->addr = -1; /* uh oh */ + } + + /* if we have buffered io */ + if ((dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) || + (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) { + + /* if receiving then this would be a repeated start + * + *if we have some bytes already + */ + if ((dev->state == I2C_STATE_SL_RX) && + (dev->i2c_slave_msg->xferred > 0) && + (dev->config_flags & I2C_SLAVE_USE_RX_BUFFER)) { + /* Call the callback with the contents of the data */ + if (dev->i2c_slave_recv_callback != NULL) { + (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg); + } + } + + /* Reset the message back to defaults. + * We are starting a new message + */ + dev->i2c_slave_msg->flags = 0; + dev->i2c_slave_msg->length = 0; + dev->i2c_slave_msg->xferred = 0; + dev->msgs_left = 0; + dev->timestamp = systick_uptime(); + + /* We have been addressed with SLA+R so + * the master wants us to transmit + */ + if ((sr1 & I2C_SR1_TXE) && + (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) { + /* Call the transmit callback so it can populate the msg + * data with the bytes to go + */ + if (dev->i2c_slave_transmit_callback != NULL) { + (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg); + } + } + dev->state = I2C_STATE_BUSY; + } + + sr1 = sr2 = 0; + } + + /* EV3: Master requesting data from slave. Transmit a byte*/ + if (sr1 & I2C_SR1_TXE) { + if (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER) { + if (dev->i2c_slave_msg->xferred >= dev->i2c_slave_msg->length) { + /* End of the transmit buffer? If so we NACK */ + i2c_disable_ack(dev); + /* We have to either issue a STOP or write something here. + * STOP here seems to screw up some masters, + * For now padding with 0 + */ + i2c_write(dev, 0); + /*i2c_stop_condition(dev); // This is causing bus lockups way more than it should !? Seems some I2C master devices freak out here*/ + } + else + { + /* NACk the last byte */ + if (dev->i2c_slave_msg->xferred == dev->i2c_slave_msg->length-1) { + i2c_disable_ack(dev); + } + else { + i2c_enable_ack(dev); + } + i2c_write(dev, dev->i2c_slave_msg->data[dev->i2c_slave_msg->xferred++]); + } + } + else + { + /* Call the callback to get the data we need. + * The callback is expected to write using i2c_write(...) + * If the slave is going to terminate the transfer, this function should + * also do a NACK on the last byte! + */ + if (dev->i2c_slave_transmit_callback != NULL) (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg); + } + + dev->state = I2C_STATE_BUSY; + sr1 = sr2 = 0; + } + + /* EV2: Slave received data from a master. Get from DR */ + if (sr1 & I2C_SR1_RXNE) { + if (dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) { + /* Fill the buffer with the contents of the data register */ + /* These is potential for buffer overflow here, so we should + * really store the size of the array. This is expensive in + * the ISR so left out for now. We must trust the implementor! + */ + dev->i2c_slave_msg->data[dev->i2c_slave_msg->xferred++] = dev->regs->DR; + dev->i2c_slave_msg->length++; + } + else { + /* Call the callback with the contents of the data */ + dev->i2c_slave_msg->data[0] = dev->regs->DR; + if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg); + } + dev->state = I2C_STATE_SL_RX; + sr1 = sr2 = 0; + } + + /* EV4: Slave has detected a STOP condition on the bus */ + if (sr1 & I2C_SR1_STOPF) { + dev->regs->CR1 |= I2C_CR1_PE; + + if ((dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) || + (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) { + + /* The callback with the data will happen on a NACK of the last data byte. + * This is handled in the error IRQ (AF bit) + */ + /* Handle the case where the master misbehaves by sending no NACK */ + if (dev->state != I2C_STATE_IDLE) { + if (dev->state == I2C_STATE_SL_RX) { + if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg); + } + else { + if (dev->i2c_slave_transmit_callback != NULL) (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg); + } + } + } + + sr1 = sr2 = 0; + dev->state = I2C_STATE_IDLE; + } + + return; + } + + /* * EV5: Start condition sent */ if (sr1 & I2C_SR1_SB) { @@ -447,6 +646,7 @@ void _i2c_irq_handler(i2c_dev *dev) { } } } + } /* @@ -456,10 +656,49 @@ void _i2c_irq_handler(i2c_dev *dev) { void _i2c_irq_error_handler(i2c_dev *dev) { I2C_CRUMB(ERROR_ENTRY, dev->regs->SR1, dev->regs->SR2); - dev->error_flags = dev->regs->SR2 & (I2C_SR1_BERR | + dev->error_flags = dev->regs->SR1 & (I2C_SR1_BERR | I2C_SR1_ARLO | I2C_SR1_AF | I2C_SR1_OVR); + + /* Are we in slave mode? */ + if ((dev->regs->SR2 & I2C_SR2_MSL) != I2C_SR2_MSL) { + /* Check to see if the master device did a NAK on the last bit + * This is perfectly valid for a master to do this on the bus. + * We ignore this. Any further error processing takes us into dead + * loop waiting for the stop condition that will never arrive + */ + if (dev->regs->SR1 & I2C_SR1_AF) { + /* Clear flags */ + dev->regs->SR1 = 0; + dev->regs->SR2 = 0; + /* We need to write something to CR1 to clear the flag. + * This isn't really mentioned but seems important */ + i2c_enable_ack(dev); + + if (dev->state == I2C_STATE_SL_RX && + dev->config_flags & I2C_SLAVE_USE_RX_BUFFER && + dev->i2c_slave_msg->xferred > 0) { + /* Call the callback with the contents of the data */ + if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg); + } + + dev->state = I2C_STATE_IDLE; + return; + } + /* Catch any other strange errors while in slave mode. + * I have seen BERR caused by an over fast master device + * as well as several overflows and arbitration failures. + * We are going to reset SR flags and carry on at this point which + * is not the best thing to do, but stops the bus locking up completely + * If we carry on below and send the stop bit, the code spins forever */ + /* Clear flags */ + dev->regs->SR1 = 0; + dev->regs->SR2 = 0; + dev->state = I2C_STATE_IDLE; + return; + } + /* Clear flags */ dev->regs->SR1 = 0; dev->regs->SR2 = 0; @@ -507,3 +746,31 @@ static void set_ccr_trise(i2c_dev *dev, uint32 flags) { i2c_set_clk_control(dev, ccr); i2c_set_trise(dev, trise); } + + +/** + * @brief callback for when the device acts as a slave. If using an rx buffer, this is triggered + * after the last byte, otherwise it is called for every incoming packet. + * @param dev I2C device + * @param msg The dev_msg to pass to the slave init code + * @param func The function pointer to call + */ +void i2c_slave_attach_recv_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_recv_callback_func func) { + dev->i2c_slave_recv_callback = func; + dev->i2c_slave_msg = msg; + msg->xferred = 0; +} + + +/** + * @brief callback for when the device acts as a slave. If using a tx buffer, this is triggered + * after the device is successsfully addressed with SLA+R. + * @param dev I2C device + * @param msg The dev_msg to pass to the slave init code + * @param func The function pointer to call + */ +void i2c_slave_attach_transmit_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_transmit_callback_func func) { + dev->i2c_slave_transmit_callback = func; + dev->i2c_slave_msg = msg; + msg->xferred = 0; +} diff --git a/libmaple/include/libmaple/i2c.h b/libmaple/include/libmaple/i2c.h index ff1c313..fbb4c09 100644 --- a/libmaple/include/libmaple/i2c.h +++ b/libmaple/include/libmaple/i2c.h @@ -29,12 +29,19 @@ * @file libmaple/include/libmaple/i2c.h * @brief Inter-Integrated Circuit (I2C) peripheral support * - * Currently master-only. Usage notes: + * Supports Master and Slave. + * Master Usage notes: * * - Enable an I2C device with i2c_master_enable(). * - Initialize an array of struct i2c_msg to suit the bus * transactions (reads/writes) you wish to perform. * - Call i2c_master_xfer() to do the work. + * + * Slave Usage notes: + * - Enable I2C slave by calling i2c_slave_enable(). + * Check flags for usage. Enabling master also enabled slave. + * - initialise the i2c_msg struct and the data buffer + * - initialise the callback functions */ #ifndef _LIBMAPLE_I2C_H_ @@ -93,6 +100,7 @@ typedef struct i2c_msg { #define I2C_MSG_READ 0x1 #define I2C_MSG_10BIT_ADDR 0x2 + /** * Bitwise OR of: * - I2C_MSG_READ (write is default) @@ -197,7 +205,12 @@ typedef struct i2c_msg { #define I2C_DUTY_16_9 0x2 // 16/9 duty ratio /* Flag 0x4 is reserved; DO NOT USE. */ #define I2C_BUS_RESET 0x8 // Perform a bus reset +#define I2C_SLAVE_USE_RX_BUFFER 0x10 // Use a buffered message when doing a slave recv +#define I2C_SLAVE_USE_TX_BUFFER 0x20 // Use a buffered message when doing a slave transmit +#define I2C_SLAVE_DUAL_ADDRESS 0x40 // Enable the dual slave address scheme +#define I2C_SLAVE_GENERAL_CALL 0x80 // Enable the general call on address 0x00 void i2c_master_enable(i2c_dev *dev, uint32 flags); +void i2c_slave_enable(i2c_dev *dev, uint32 flags); #define I2C_ERROR_PROTOCOL (-1) #define I2C_ERROR_TIMEOUT (-2) @@ -406,6 +419,53 @@ static inline void i2c_set_trise(i2c_dev *dev, uint32 trise) { dev->regs->TRISE = trise; } +/* + * Slave support + */ + +/** + * @brief Enable Dual addressing mode to allow peripheral to have 2 addresses + * @param dev I2C device + */ +static inline void i2c_slave_dual_address_enable(i2c_dev *dev) { + dev->regs->OAR2 |= I2C_OAR2_ENDUAL; +} + +/** + * @brief Enable General Call to allow the unit to respond on addr 0x00 + * @param dev I2C device + */ +static inline void i2c_slave_general_call_enable(i2c_dev *dev) { + dev->regs->CR1 |= I2C_CR1_ENGC; +} + +/* callback functions */ +/* Callback handler for data received over the bus */ +void i2c_slave_attach_recv_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_recv_callback_func func); + +/* Callback handler for data being requested over the bus + * The callback function must call i2c_write to get the data over the bus + */ +void i2c_slave_attach_transmit_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_transmit_callback_func func); + +/** + * @brief Set the primary I2c slave address + * @param dev I2C device + * @param address the 8 or 10 bit i2c address + */ +static inline void i2c_slave_set_own_address(i2c_dev *dev, uint16 address) { + dev->regs->OAR1 = address <<1; +} + +/** + * @brief Set the secondary I2c slave address + * @param dev I2C device + * @param address the 8 or 10 bit i2c address + */ +static inline void i2c_slave_set_own_address2(i2c_dev *dev, uint16 address) { +dev->regs->OAR2 = (address <<1 ) | I2C_OAR2_ENDUAL; +} + #ifdef __cplusplus } #endif diff --git a/libmaple/include/libmaple/i2c_common.h b/libmaple/include/libmaple/i2c_common.h index 17cabe3..93e17e2 100644 --- a/libmaple/include/libmaple/i2c_common.h +++ b/libmaple/include/libmaple/i2c_common.h @@ -52,9 +52,12 @@ typedef enum i2c_state { I2C_STATE_IDLE = 1, /**< Idle */ I2C_STATE_XFER_DONE = 2, /**< Done with transfer */ I2C_STATE_BUSY = 3, /**< Busy */ + I2C_STATE_SL_RX = 4, /**< Slave receiving */ I2C_STATE_ERROR = -1 /**< Error occurred */ } i2c_state; +typedef void (*i2c_slave_recv_callback_func)(struct i2c_msg *); +typedef void (*i2c_slave_transmit_callback_func)(struct i2c_msg *); /** * @brief I2C device type. */ @@ -88,6 +91,17 @@ typedef struct i2c_dev { nvic_irq_num ev_nvic_line; /**< Event IRQ number */ nvic_irq_num er_nvic_line; /**< Error IRQ number */ volatile i2c_state state; /**< Device state */ + uint32 config_flags; /**< Configuration flags */ + + /* + * Slave implementation. Callback functions in this struct allow + * for a separate callback function for each I2C unit available onboard + */ + i2c_slave_transmit_callback_func i2c_slave_transmit_callback; + i2c_slave_recv_callback_func i2c_slave_recv_callback; + + struct i2c_msg *i2c_slave_msg; /* the message that the i2c slave will use */ + } i2c_dev; #endif |