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i2c slave tx now working, see #99 #100

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merged 3 commits into from
Jun 11, 2023
Merged

i2c slave tx now working, see #99 #100

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b6927bc
i2c slave tx now working, see ssues/99
RoboDurden Jun 11, 2023
1740e04
two little things in i2c_slave_write_buffer fixed
RoboDurden Jun 11, 2023
e6bc855
obj_s->tx_count += length; after the loop
RoboDurden Jun 11, 2023
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12 changes: 10 additions & 2 deletions libraries/Wire/src/Wire.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -299,15 +299,23 @@ void TwoWire::onRequestService(void* pWireObj)
TwoWire* pWire = (TwoWire*) pWireObj;
// don't bother if user hasn't registered a callback
if (pWire->user_onRequest) {
// reset tx buffer iterator vars
// reset master tx buffer iterator vars
// !!! this will kill any pending pre-master sendTo() activity
pWire->_tx_buffer.head = 0;
pWire->_tx_buffer.tail = 0;

// reset slave tx buffer iterator vars
pWire->_i2c.tx_buffer_ptr = pWire->_tx_buffer.buffer;
pWire->_i2c.tx_count = 0;

// alert user program
pWire->user_onRequest();
}

// reset slave tx buffer iterator to let interrupt transmit the buffer
pWire->_i2c.tx_buffer_ptr = pWire->_tx_buffer.buffer;
}
}

// sets function called on slave write
void TwoWire::onReceive(void (*function)(int))
{
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24 changes: 8 additions & 16 deletions libraries/Wire/src/utility/twi.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -541,26 +541,18 @@ void i2c_attach_slave_tx_callback(i2c_t *obj, void (*function)(void*), void* pWi
* @param length Number of bytes to read
* @return status
*/
i2c_status_enum i2c_slave_write_buffer(i2c_t *obj, uint8_t *data, uint16_t length)
{
i2c_status_enum i2c_slave_write_buffer(i2c_t *obj, uint8_t *data, uint16_t length){
struct i2c_s *obj_s = I2C_S(obj);
uint8_t i = 0;
i2c_status_enum ret = I2C_OK;
if ( (obj_s->tx_count + length) > obj->tx_rx_buffer_size)
return I2C_DATA_TOO_LONG;
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I think incrementing tx_count should only happen if we know that we can hold the data, otherwise we get into an inconstistent state if we increment + return error. I.e., first check if (obj_s->tx_count + length <= obj->tx_rx_buffer_size), then increment.


if (length > obj->tx_rx_buffer_size) {
ret = I2C_DATA_TOO_LONG;
} else {
/* check the communication status */
for (i = 0; i < length; i++) {
*obj_s->tx_buffer_ptr++ = *(data + i);
}
obj_s->tx_count = length;
obj_s->tx_buffer_ptr = obj_s->tx_buffer_ptr - length;
}
return ret;
uint8_t i = 0;
for (i; i < length; i++)
*obj_s->tx_buffer_ptr++ = *(data + i);
obj_s->tx_count += length;
return I2C_OK;
}


/** Check the I2C bus to see if it's busy
*
* @param obj The I2C object
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