VREFBUF enable for STM32L476VG not possible?

[Merlin Ma]

Posted on May 02, 2017 at 10:54

I am using a STM32L476VG (100 pin package, VREF+ not bonded to VDDA) for a mixed signal design. I planed to use the VREF+ as a 2.048V reference output. Currently there is no load on the VREF+ pin.

Unfortunately I always get a HAL_TIMEOUT while waiting for the VRR bit in the VREFBUF CSR register:

HAL_SYSCFG_VREFBUF_VoltageScalingConfig(SYSCFG_VREFBUF_VOLTAGE_SCALE0);
HAL_SYSCFG_VREFBUF_HighImpedanceConfig(SYSCFG_VREFBUF_HIGH_IMPEDANCE_DISABLE);
if (HAL_SYSCFG_EnableVREFBUF() != HAL_OK)
{
Error_Handler(ENVREFO_ERROR);
}�?�?�?�?�?�?

Also no voltage output is measureable at the VREF+ pin...

Do I miss something here? I tried to change the order or manually set the registers (without time-out) but no output at all.

Thank you for your help!!

Best regards,

Merlin

#analog #vrefbuf #reference #vref+ #csr

[Merlin Ma · Accepted solution]

Posted on May 04, 2017 at 10:40

For everyone having the same problem:

Enable clock for SYSCFG: Set bit 0 in RCC_APB2ENR before enabling the VREFBuffer.