how do i work the I2C peripheral on STM32L412 - embedded

Question

I'm trying to get a 4 channel DAC working through the I2C peripheral on an STM32L412, I've read through the reference manual but I'm a little confused and my I2C doesn't work. So far, it sends out the first address byte OK, it seems like there's an ACK bit, but then nothing - just a stop condition. I'm trying to output 8 bytes - four 12bit values split over two bytes each.
I've set it up using the STM32cube but I found I had write a few things manually afterward - below is the initialisation. I'm operating in fast mode, 400KHz - ive used 300nS as the rise / fall times and the peripheral is clocked at 16MHz
Can anyone help me? I don't know what im doing wrong
static void MX_I2C2_Init(void)
{
hi2c2.Instance = I2C2;
hi2c2.Init.Timing = 0x00610611;
hi2c2.Init.OwnAddress1 = 192;
hi2c2.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c2.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c2.Init.OwnAddress2 = 0;
hi2c2.Init.OwnAddress2Masks = I2C_OA2_NOMASK;
hi2c2.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c2.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c2) != HAL_OK)
{
Error_Handler();
}
/** Configure Analogue filter
*/
if (HAL_I2CEx_ConfigAnalogFilter(&hi2c2, I2C_ANALOGFILTER_ENABLE) != HAL_OK)
{
Error_Handler();
}
/** Configure Digital filter
*/
if (HAL_I2CEx_ConfigDigitalFilter(&hi2c2, 0) != HAL_OK)
{
Error_Handler();
}
}
i've included this in the main setup before the loop
I2C2->TXDR = DACdata[0]; //pre-load output register
I2C2 ->CR2 &= ~(1<<25); //AUTOLOAD = 0
I2C2 ->CR2 |= 0b1100000<<1; //enter slave address
I2C2 ->CR1 |= 1 << 6 | 1<<1; //enable finish interrupts
I2C2 ->CR2 |= 0b1000 << 16; //bytes to send = 8
I2C2 ->CR2 |= 1<<13; //start DAC
and this is my interrupt, but the program never gets here
void I2C2_EV_IRQHandler(void)
{
if (I2C2->ISR & 1<<1)
{
i2ccounter++;
I2C2->TXDR = DACdata[i2ccounter];
}
if (I2C2->ISR & 1<<6)
{
i2ccounter = 0;
I2C2->TXDR = DACdata[0];
I2C2 ->CR2 |= 1<<13; //start counter
}
HAL_I2C_EV_IRQHandler(&hi2c2);
}
and the main loop
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_I2C2_Init();
MX_ADC1_Init();
MX_TIM1_Init();
MX_TIM2_Init();
I2C2->TXDR = DACdata[0]; //pre-load output register
I2C2 ->CR2 &= ~(1<<25); //autoend off
I2C2 ->CR2 |= 0b1100000<<1; //enter slave address
I2C2 ->CR1 |= 1 << 6 | 1<<1; //enable finish interrupts
I2C2 ->CR2 |= 0b1000 << 16; //bytes to send = 8
I2C2 ->CR2 |= 1<<13; //start DAC
while (1)
{
}
}