using variables / constants in .ioc file from main?

You can't go from code to IOC file, only from IOC to code.

If you put your definitions within USER CODE sections, they will not be overwritten, barring CubeMX bugs. Any modifications outside of these sections are overwritten.

Not sure how I would do this.....Below is a trivial example of what I mean....The CubeMx generates the following code.....

static void MX_RTC_Init(void)
{
 
 /* USER CODE BEGIN RTC_Init 0 */
 
 /* USER CODE END RTC_Init 0 */
 
 /* USER CODE BEGIN RTC_Init 1 */
 
 /* USER CODE END RTC_Init 1 */
 /** Initialize RTC Only
 */
 hrtc.Instance = RTC;
 hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
 hrtc.Init.AsynchPrediv = CFG_RTC_ASYNC_PRELOAD;
 hrtc.Init.SynchPrediv = CFG_RTC_SYNC_PRELOAD;
 hrtc.Init.OutPut = RTC_OUTPUT_DISABLE;
 hrtc.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
 hrtc.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
 hrtc.Init.OutPutRemap = RTC_OUTPUT_REMAP_NONE;
 if (HAL_RTC_Init(&hrtc) != HAL_OK)
 {
 Error_Handler();
 }
 /* USER CODE BEGIN RTC_Init 2 */
 
 /* USER CODE END RTC_Init 2 */
 
}

Suppose for example sake I want to change the line above to:

hrtc.Init.AsynchPrediv = 127;

Where do you suggest I do this??? If I were to do this in USER CODE Block 2 I would have to call the HAL_RTC_init function again. Obviously I cannot do this in block 0 or 1 or it gets overwritten with the above code???

thanks

steve

You can define a user constant and use that for the value instead of a numeric value. Maybe that's what you're looking for?

But if you change the numeric value in the code, the IOC isn't updated and it'll be overwritten when you regenerate. You could change the value in the IOC and regenerate to update it.

Some CubeMX config fields have "validation" options. If you click on a field, say the "Asynchronous Predivider Value" line under RTC, look for a little plus sign in a circle at the right hand edge of that line. Click on that "+" and select "No Check". You can then enter any value you want, including any define that you have elsewhere in the code. I use this is set the I2C slave addresses. For example, I'll have in my code:

#define FLAMMERJAMMER_I2C_ADDRESS 0x5c

then in CubeMX, I will set the "Primary Slave Address" field to "FLAMMERJAMMER_I2C_ADDRESS" instead of a hard-coded decimal or hex value.

Thank you for all the responses....I think I got it.