diff options
| -rw-r--r-- | CREDITS | 12 | ||||
| -rw-r--r-- | examples/i2c_slave_example.cpp | 110 | ||||
| -rw-r--r-- | libmaple/i2c.c | 4 | ||||
| -rw-r--r-- | libmaple/include/libmaple/i2c.h | 1 |
4 files changed, 121 insertions, 6 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 @@ -81,9 +86,4 @@ W: http://sarup.dk/index.html N: Andy Scott ("xttocs") E: andy.g.scott@gmail.com D: LiquidCrystal library - -N: Barry Carter ("ginge") -E: barry.carter@gmail.com -D: Added i2C slave support -W: headfuzz.co.uk -
\ No newline at end of file + 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 6c609d9..bbbf123 100644 --- a/libmaple/i2c.c +++ b/libmaple/i2c.c @@ -458,6 +458,10 @@ void _i2c_irq_handler(i2c_dev *dev) { 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++; } diff --git a/libmaple/include/libmaple/i2c.h b/libmaple/include/libmaple/i2c.h index 5a9da58..fbb4c09 100644 --- a/libmaple/include/libmaple/i2c.h +++ b/libmaple/include/libmaple/i2c.h @@ -210,6 +210,7 @@ typedef struct i2c_msg { #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) |