How to use the STM32CUBE HAL library for a coninuouse i2c read - i2c

Question

i am using the actual HAL library to read from and write to an AD7998 analog to digital converter with a stm32f407 discovery board.
If I want to read several register values from the conversion result register, the manual says that the SCL and SDA signal should be maintained and I must not send a stop bit.
AD7998 signal pattern to read several register values of one register.
I have tried to use Mem_Read. That seems to work for one 2 bytes register. But now i am not sure how to access the other parts of the conversion result registers to read more than the first channel.
If necessary, you can find the manual here -> AD7998 manual, and my code below.
I tried to increase the number of bytes to read, but then the value of the first channel is written to the other bytes.
Has anybody of you tried this before?
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "i2c.h"
#include "i2s.h"
#include "tim.h"
#include "usb_device.h"
#include "gpio.h"
/* USER CODE BEGIN PV */
uint16_t DeviceAdress= 0x20 << 1;
/* USER CODE END PV */
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
HAL_StatusTypeDef stat = 0;
uint8_t adcTxBuffer[16];
uint8_t adcRxBuffer[16];
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_I2C1_Init();
MX_I2S3_Init();
MX_SPI1_Init();
MX_USB_DEVICE_Init();
MX_TIM14_Init();
/* USER CODE BEGIN 2 */
adcTxBuffer[0] = 0x00;
adcTxBuffer[1] = 0xF8; // setup 4 channels (0, 1, 2, 3)
stat = HAL_I2C_Mem_Write(&hi2c1, DeviceAdress, 0x02, 2, adcTxBuffer, 2, 100); //access the configuration register
stat = HAL_I2C_Mem_Read(&hi2c1, DeviceAdress, 0x02, 2, adcRxBuffer, 2, 100); // read vlaue from Configuration Register
HAL_GPIO_TogglePin(GPIOA, 1); // start up adc
HAL_Delay(1); // delay for adc power up
HAL_GPIO_TogglePin(GPIOA, 1); // delay for sampling complete
HAL_Delay(1); // delay for sampling complete
stat = HAL_I2C_Mem_Read(&hi2c1, DeviceAdress, 0x00, 2, adcRxBuffer, 16, 100); // read conversion result register
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* #brief System Clock Configuration
* #retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
/** Configure the main internal regulator output voltage
*/
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 8;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 7;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
{
Error_Handler();
}
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_I2S;
PeriphClkInitStruct.PLLI2S.PLLI2SN = 192;
PeriphClkInitStruct.PLLI2S.PLLI2SR = 2;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
{
Error_Handler();
}
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* #brief This function is executed in case of error occurrence.
* #retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* #brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* #param file: pointer to the source file name
* #param line: assert_param error line source number
* #retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
tex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Answer 1

Found an alternative way to read the data, by configuring my register in each iteration. Works fine now.