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EPR request in STM32G071

Jaroslaw_T
Associate III

‎2026-03-31 4:00 AM - edited ‎2026-03-31 4:01 AM

Hello

I have my own board with STM32G071KBT6 microcontroller. I successfully comunicate with charger by PD protocol and I receive up to 21 V (PPS). But I need above 21V. I have power bank with AVS up to 28V and USB cable with e-marker (up to 240W). How to configure the stack to receive EPR parameters? I have no TCPP IC, but I use my own protection circuit. In the trace the EPR commands isn't present. I use STM32CubeIDE 2.1.1 and STM32CubeMX 6.17.0.

Thanks a lot and best regards

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13 REPLIES 13
FBL
ST Employee

‎2026-03-31 7:24 AM - edited ‎2026-03-31 12:39 PM

Hi @Jaroslaw_T 

Thank you for the question.

I'm working on new knowledge base article on How to create an EPR capable USB PD Source and Sink on STM32 using TCPP ports . For demo, VBUS is kept at 5 V even for higher SPR/EPR PDOs; only the protocol is exercised (not full EPR explicit contract).

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.




Best regards,
FBL
epr_src.txt
Jaroslaw_T
Associate III

‎2026-04-03 2:00 AM

Is any way to receive PDO and APDO greater than 21V PPS? Unfortunatelly I have in my trace messages with max APDO 21V and PDO 20V.

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FBL
ST Employee

‎2026-04-06 2:09 AM

Hello @Jaroslaw_T 

You need to redefine PDO to support EPR:

uint32_t PORT0_PDO_ListSRC[USBPD_MAX_NB_PDO] =
{
#ifndef _EPR_SRC
  /* PDO 1 */ (0x00019096U),
#else /*_EPR_SRC*/
 /* PDO 1 */
        ( ((PWR_A_10MA(USBPD_CORE_PDO_SRC_FIXED_MAX_CURRENT)) << USBPD_PDO_SRC_FIXED_MAX_CURRENT_Pos) |
          ((PWR_V_50MV(5)) << USBPD_PDO_SRC_FIXED_VOLTAGE_Pos)             |
          USBPD_PDO_SRC_FIXED_PEAKCURRENT_EQUAL                            |
#if defined(_EPR_SRC)
          USBPD_PDO_SRC_FIXED_EPR_SUPPORTED                                |
#endif /* _EPR_SRC */
#if defined(USBPD_REV30_SUPPORT)
#if defined(_UNCHUNKED_SUPPORT)
          USBPD_PDO_SRC_FIXED_UNCHUNK_SUPPORTED                               |
#else
          USBPD_PDO_SRC_FIXED_UNCHUNK_NOT_SUPPORTED                        |
#endif /* _UNCHUNKED_SUPPORT */
#endif /*USBPD_REV30_SUPPORT*/
          USBPD_PDO_SRC_FIXED_DRD_NOT_SUPPORTED                            |
#ifdef _USB_HOST
          USBPD_PDO_SRC_FIXED_USBCOMM_SUPPORTED                            |
#else
          USBPD_PDO_SRC_FIXED_USBCOMM_NOT_SUPPORTED                        |
#endif
          USBPD_PDO_SRC_FIXED_EXT_POWER_NOT_AVAILABLE                            |  
          USBPD_PDO_SRC_FIXED_USBSUSPEND_NOT_SUPPORTED                     |
          USBPD_PDO_SRC_FIXED_DRP_NOT_SUPPORTED                            |
          USBPD_PDO_TYPE_FIXED
        ),
  /* PDO 2 */(0x00000000U),
  /* PDO 3 */(0x00000000U),
  /* PDO 4 */(0x00000000U),
  /* PDO 5 */ (0x00000000U),
  /* PDO 6 */ (0x00000000U),
  /* PDO 7 */ (0x00000000U)
};

 

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.




Best regards,
FBL
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Jaroslaw_T
Associate III

‎2026-04-06 9:22 PM - edited ‎2026-04-07 1:45 AM

Thank You, but I have sink device, not source.

Will the USB PD stack for STM32G0 support PD3.1 (EPR mode)? I have project with STM32G0 microcontroller because of low cost and unfortunatelly I can't use other uC.

I read that X-CUBE-TCPP supports PD3.1, but how to use it without any TCPP IC? Is it posiible any way.

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Jaroslaw_T
Associate III

‎2026-04-09 12:26 AM - edited ‎2026-04-09 12:30 AM

Now I have downloaded the MW from github.com page: https://github.com/STMicroelectronics/stm32-mw-usbpd-core/tree/main and after the files update the EPR mode seems to be working.

In my code (usbpd_dpm_user.c):

USBPD_StatusTypeDef USBPD_DPM_UserInit(void)
{
/* USER CODE BEGIN USBPD_DPM_UserInit */
	DPM_Params[0].PE_SpecRevision=USBPD_SPECIFICATION_REV3;
	DPM_Settings[0].PE_PD3_Support.d.Is_EPR_Supported_SNK=USBPD_TRUE;
	return USBPD_OK;
/* USER CODE END USBPD_DPM_UserInit */
}

In function USBPD_DPM_Notification:

switch(EventVal)
  {
    case USBPD_NOTIFY_POWER_EXPLICIT_CONTRACT :
    {
    	USBPD_PE_Request_EPRModeEnter(PortNum);
    }
      break;

In function USBPD_DPM_SNK_EvaluateCapabilities:

USBPD_SNKRDO_TypeDef rdo;
	rdo.d32=0U;
	if(DPM_Settings[PortNum].PE_PD3_Support.d.Is_EPR_Supported_SNK==USBPD_TRUE&&DPM_Params[PortNum].PE_SpecRevision>=USBPD_SPECIFICATION_REV3)
	{
		rdo.FixedVariableRDO.EPR_Capable=1U;
	}
	else
	{
		rdo.FixedVariableRDO.EPR_Capable=0U;
	}

 

By the way - will the middleware update be officially available as an STM32Cube package update?

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Jaroslaw_T
Associate III

‎2026-04-09 11:17 PM - edited ‎2026-04-22 4:54 AM

Hello, I'm able to enter in EPR mode, as below:

CAD	2	1	USBPD_CAD_STATE_DETACHED	850	
CAD	4	1	USBPD_CAD_STATE_ATTACHED_WAIT	851	
CAD	123	1	USBPD_CAD_STATE_ATTACHED	852	
NOTIF	123	1	USBSTACK_START	853	
DEBUG	123	1	ADVICE: USBPD_DPM_Notification:104	854	
EVENT	123	1	EVENT_ATTACHED	855	
DEBUG	123	1	ADVICE: update USBPD_DPM_UserCableDetection	856	
DEBUG	123	1	ADVICE: update USBPD_DPM_SetDataInfo:2	857	
DEBUG	123	1	ADVICE: update USBPD_DPM_SetDataInfo:6	858	
PE	124	1	PE_SNK_STARTUP	859	
PE	124	1	PE_SNK_WAIT_FOR_CAPABILITIES	860	
IN	146	1	SOP	 PD3	s:030	    H:0x71A1    	(id:0, DR:DFP, PR:SRC) 	SRC_CAPABILITIES	DATA: 2C9181282CD102002CC103002CB10400F44106003C21DCC03C21A4C1	
Option: 	EPW	DRP	
 [1] Fixed : 5V - 3A
 [2] Fixed : 9V - 3A
 [3] Fixed : 12V - 3A
 [4] Fixed : 15V - 3A
 [5] Fixed : 20V - 5A
 [6] Programmable : [3.3V - 11V] - 3A
 [7] Programmable : [3.3V - 21V] - 3A
	861	
OUT	146	1	SOP	s:002	    H:0x0081     (id:0, DR:UFP, PR:SNK) 	GOODCRC	862	
DEBUG	147	1	Received: 28 bytes	863	
DEBUG	147	1	PDO[1] = 5000 mV, 3000 mA, 15 W	864	
DEBUG	147	1	PDO[2] = 9000 mV, 3000 mA, 27 W	865	
DEBUG	147	1	PDO[3] = 12000 mV, 3000 mA, 36 W	866	
DEBUG	148	1	PDO[4] = 15000 mV, 3000 mA, 45 W	867	
DEBUG	148	1	PDO[5] = 20000 mV, 5000 mA, 100 W	868	
DEBUG	148	1	APDO [6] - max voltage: 11000 mV	869	
DEBUG	148	1	APDO [7] - max voltage: 21000 mV	870	
PE	148	1	PE_SNK_EVALUATE_CAPABILITY	871	
PE	149	1	PE_SNK_SEND_REQUEST	872	
OUT	149	1	SOP	 PD3	REQUEST	s:006	    H:0x1082    	(id:0, DR:UFP, PR:SNK)  DATA: F4D14753
ObjectPosition:5
GiveBack:0
CapabilityMismatch:0
USBCommunicationCapable:1
NoUSBSuspend:1
UnchunkedExtendedMessagesSupported:0
MaximumOperatingCurrent:5000mA
OperatingCurrent:5000mA	873	
IN	150	1	SOP	s:002	    H:0x0161     (id:0, DR:DFP, PR:SRC) 	GOODCRC	874	
PE	150	1	PE_SNK_SELECT_CAPABILITY	875	
IN	152	1	SOP	 PD3	ACCEPT	s:002	    H:0x03A3     (id:1, DR:DFP, PR:SRC) 	876	
OUT	152	1	SOP	s:002	    H:0x0281     (id:1, DR:UFP, PR:SNK) 	GOODCRC	877	
NOTIF	153	1	POWER_STATE_CHANGE	878	
DEBUG	153	1	ADVICE: USBPD_DPM_Notification:90	879	
NOTIF	153	1	REQUEST_ACCEPTED	880	
DEBUG	153	1	ADVICE: USBPD_DPM_Notification:1	881	
PE	153	1	PE_SNK_TRANSITION_SNK	882	
IN	449	1	SOP	 PD3	PS_RDY	s:002	    H:0x05A6     (id:2, DR:DFP, PR:SRC) 	883	
OUT	449	1	SOP	s:002	    H:0x0481     (id:2, DR:UFP, PR:SNK) 	GOODCRC	884	
NOTIF	450	1	POWER_STATE_CHANGE	885	
DEBUG	450	1	ADVICE: USBPD_DPM_Notification:90	886	
NOTIF	450	1	POWER_EXPLICIT_CONTRACT	887	
PE	450	1	PE_STATE_READY	888	
NOTIF	450	1	STATE_SNK_READY	889	
DEBUG	450	1	ADVICE: USBPD_DPM_Notification:32	890	
PE	450	1	PE_STATE_SEND_EPRMODE	891	
DEBUG	450	1	ADVICE: update USBPD_DPM_GetDataInfo:30	892	
OUT	450	1	SOP	s:006	 PD3	    H:0x128A    	(id:1, DR:UFP, PR:SNK) 	EPR_MODE	
EPR_MODE : 01000000
	Action:	01
		 0x01 Enter Sink only
		 0x02 Enter Acknowledged Source only
		 0x03 Enter Succeeded Source only
		 0x04 Enter Failed Source only
		 0x05 Exit Sink or Source
	Data:	00
		 0x00 - Unknown cause
		 0x01 - Cable not EPR capable
		 0x02 - Source failed to become VCONN source
		 0x03 - EPR Mode Capable bit not set in RDO
		 0x04 - Source unable to enter EPR Mode at this time
		 0x05 - EPR Mode Capable bit not set in PDO
	893	
IN	452	1	SOP	s:002	    H:0x03A1     (id:1, DR:DFP, PR:SRC) 	GOODCRC	894	
PE	452	1	PE_STATE_WAIT_EPRMODE_ACK	895	
IN	453	1	SOP	s:006	 PD3	    H:0x17AA    	(id:3, DR:DFP, PR:SRC) 	EPR_MODE	
EPR_MODE : 02000000
	Action:	02
		 0x01 Enter Sink only
		 0x02 Enter Acknowledged Source only
		 0x03 Enter Succeeded Source only
		 0x04 Enter Failed Source only
		 0x05 Exit Sink or Source
	Data:	00
		 0x00 - Unknown cause
		 0x01 - Cable not EPR capable
		 0x02 - Source failed to become VCONN source
		 0x03 - EPR Mode Capable bit not set in RDO
		 0x04 - Source unable to enter EPR Mode at this time
		 0x05 - EPR Mode Capable bit not set in PDO
	896	
OUT	453	1	SOP	s:002	    H:0x0681     (id:3, DR:UFP, PR:SNK) 	GOODCRC	897	
DEBUG	453	1	ADVICE: update USBPD_DPM_SetDataInfo:23	898	
NOTIF	453	1	NOTIFY_EPRMODE_ACK	899	
DEBUG	453	1	ADVICE: USBPD_DPM_Notification:113	900	
IN	469	1	SOP	s:006	 PD3	    H:0x11AA    	(id:0, DR:DFP, PR:SRC) 	EPR_MODE	
EPR_MODE : 03000000
	Action:	03
		 0x01 Enter Sink only
		 0x02 Enter Acknowledged Source only
		 0x03 Enter Succeeded Source only
		 0x04 Enter Failed Source only
		 0x05 Exit Sink or Source
	Data:	00
		 0x00 - Unknown cause
		 0x01 - Cable not EPR capable
		 0x02 - Source failed to become VCONN source
		 0x03 - EPR Mode Capable bit not set in RDO
		 0x04 - Source unable to enter EPR Mode at this time
		 0x05 - EPR Mode Capable bit not set in PDO
	901	
OUT	469	1	SOP	s:002	    H:0x0081     (id:0, DR:UFP, PR:SNK) 	GOODCRC	902	
PE	469	1	PE_STATE_WAIT_EPRMODE_STATUS	903	
DEBUG	469	1	ADVICE: update USBPD_DPM_SetDataInfo:23	904	
NOTIF	469	1	NOTIFY_EPRMODE_SUCCEEDED	905	
DEBUG	469	1	ADVICE: USBPD_DPM_Notification:114	906	
PE	470	1	PE_SNK_WAIT_FOR_CAPABILITIES	907	
IN	471	1	SOP	s:030	 PD3	    H:0xF3B1    	(id:1, DR:DFP, PR:SRC) 	EXT_EPR_SOURCE_CAPA	EXT:CNu0Ch1CReq0DSiz32 [ CHUNK BEGIN ] 	DATA: 2C9181282CD102002CC103002CB10400F44106003C21DCC03C21	908	
OUT	471	1	SOP	s:002	    H:0x0281     (id:1, DR:UFP, PR:SNK) 	GOODCRC	909	
OUT	473	1	SOP	s:006	 PD3	    H:0x9491    	(id:2, DR:UFP, PR:SNK) 	EXT_EPR_SOURCE_CAPA	EXT:CNu1Ch1CReq1DSiz0	DATA: 0000	910	
IN	474	1	SOP	s:002	    H:0x05A1     (id:2, DR:DFP, PR:SRC) 	GOODCRC	911	
IN	475	1	SOP	s:014	 PD3	    H:0xB5B1    	(id:2, DR:DFP, PR:SRC) 	EXT_EPR_SOURCE_CAPA	EXT:CNu1Ch1CReq0DSiz36 [ CHUNK END ] 
 EPR SOURCE CAPA
	
 [1] Fixed : 5V - 3A
 [2] Fixed : 9V - 3A
 [3] Fixed : 12V - 3A
 [4] Fixed : 15V - 3A
 [5] Fixed : 20V - 5A
 [6] EPR : [11V - 3.3V] - 60W
 [7] EPR : [21V - 3.3V] - 60W
 [8] Fixed : 28V - 5A
 [9] EPR : [28V - 15V] - 140W
	DATA: A4C1F4C188008C9630D2	912	
OUT	475	1	SOP	s:002	    H:0x0481     (id:2, DR:UFP, PR:SNK) 	GOODCRC	913	
DEBUG	476	1	Received: 28 bytes	914	
DEBUG	476	1	PDO[1] = 5000 mV, 3000 mA, 15 W	915	
DEBUG	476	1	PDO[2] = 9000 mV, 3000 mA, 27 W	916	
DEBUG	477	1	PDO[3] = 12000 mV, 3000 mA, 36 W	917	
DEBUG	477	1	PDO[4] = 15000 mV, 3000 mA, 45 W	918	
DEBUG	477	1	PDO[5] = 20000 mV, 5000 mA, 100 W	919	
DEBUG	477	1	APDO [6] - max voltage: 11000 mV	920	
DEBUG	477	1	APDO [7] - max voltage: 21000 mV	921	
DEBUG	477	1	EPR - received: 4 bytes	922	
DEBUG	477	1	0x0088C1F4	923	
DEBUG	477	1	EPR - max voltage: 6800 mV	924	
PE	477	1	PE_SNK_EVALUATE_CAPABILITY	925	
PE	479	1	PE_SNK_SEND_REQUEST	926	
DEBUG	479	1	ADVICE: update USBPD_DPM_GetDataInfo:29	927	
OUT	479	1	SOP	 PD3	EPR_REQUEST	s:010	    H:0x2689    	(id:3, DR:UFP, PR:SNK)  DATA: F4D1475300000000
ObjectPosition:5
GiveBack:0
CapabilityMismatch:0
USBCommunicationCapable:1
NoUSBSuspend:1
UnchunkedExtendedMessagesSupported:0
MaximumOperatingCurrent:5000mA
OperatingCurrent:5000mA	928	
IN	481	1	SOP	s:002	    H:0x07A1     (id:3, DR:DFP, PR:SRC) 	GOODCRC	929	
PE	481	1	PE_SNK_SELECT_CAPABILITY	930	
IN	482	1	SOP	 PD3	ACCEPT	s:002	    H:0x07A3     (id:3, DR:DFP, PR:SRC) 	931	
OUT	482	1	SOP	s:002	    H:0x0681     (id:3, DR:UFP, PR:SNK) 	GOODCRC	932	
NOTIF	483	1	POWER_STATE_CHANGE	933	
DEBUG	483	1	ADVICE: USBPD_DPM_Notification:90	934	
NOTIF	483	1	REQUEST_ACCEPTED	935	
DEBUG	483	1	ADVICE: USBPD_DPM_Notification:1	936	
PE	483	1	PE_SNK_TRANSITION_SNK	937	
IN	777	1	SOP	 PD3	PS_RDY	s:002	    H:0x09A6     (id:4, DR:DFP, PR:SRC) 	938	
OUT	777	1	SOP	s:002	    H:0x0881     (id:4, DR:UFP, PR:SNK) 	GOODCRC	939	
NOTIF	778	1	POWER_STATE_CHANGE	940	
DEBUG	778	1	ADVICE: USBPD_DPM_Notification:90	941	
NOTIF	778	1	POWER_EXPLICIT_CONTRACT	942	
PE	778	1	PE_STATE_READY	943	
NOTIF	778	1	STATE_SNK_READY	944	
DEBUG	778	1	ADVICE: USBPD_DPM_Notification:32	945	
PE	778	1	PE_STATE_SEND_EPRMODE	946	
DEBUG	778	1	ADVICE: update USBPD_DPM_GetDataInfo:30	947	
OUT	778	1	SOP	s:006	 PD3	    H:0x188A    	(id:4, DR:UFP, PR:SNK) 	EPR_MODE	
EPR_MODE : 01000000
	Action:	01
		 0x01 Enter Sink only
		 0x02 Enter Acknowledged Source only
		 0x03 Enter Succeeded Source only
		 0x04 Enter Failed Source only
		 0x05 Exit Sink or Source
	Data:	00
		 0x00 - Unknown cause
		 0x01 - Cable not EPR capable
		 0x02 - Source failed to become VCONN source
		 0x03 - EPR Mode Capable bit not set in RDO
		 0x04 - Source unable to enter EPR Mode at this time
		 0x05 - EPR Mode Capable bit not set in PDO
	948	
IN	780	1	SOP	s:002	    H:0x09A1     (id:4, DR:DFP, PR:SRC) 	GOODCRC	949	
PE	780	1	PE_STATE_WAIT_EPRMODE_ACK	950	
IN	1743	1	HRST	951	
NOTIF	1743	1	HARDRESET_RX	952	
DEBUG	1743	1	ADVICE: USBPD_DPM_Notification:30	953	
PE	1743	1	PE_HARD_RESET_RECEIVED	954	
PE	1743	1	PE_SNK_HARD_RESET_WAIT_VSAFE_0V	955	
GUI	0		BOARD RESET BY USER	956	
CAD	4	1	USBPD_CAD_STATE_ATTACHED_WAIT	957

but unfortunately I have no access to all received EPR PDOs and APDOs.

In case

case USBPD_CORE_DATATYPE_RCV_SRC_PDO_EPR:

 

 I have only 4 bytes of data.

 

Case code:

case USBPD_CORE_DATATYPE_RCV_SRC_PDO_EPR:
  {
	  uint32_t EPR_1=0;
	  uint32_t EPR_2=0;
	  uint32_t EPR_3=0;
	  uint32_t EPR_4=0;
	  uint32_t EPR=0;
	  DPM_USER_DEBUG_TRACE(PortNum, "EPR - received: %lu bytes", Size);
	  EPR_1=0;
	  EPR_2=0;
	  EPR_3=0;
	  EPR_4=0;
	  EPR=0;
	  EPR_1=(uint32_t)Ptr[0*4U+0U]<<0;
	  EPR_2=(uint32_t)Ptr[0*4U+1U]<<8;
	  EPR_3=(uint32_t)Ptr[0*4U+2U]<<16;
	  EPR_4=(uint32_t)Ptr[0*4U+3U]<<24;
	  EPR=EPR_1|EPR_2|EPR_3|EPR_4;
	  DPM_USER_DEBUG_TRACE(PortNum, "0x%08lX", EPR);
	  uint32_t Max_Voltage_100mV=(EPR>>17);
	  Max_Voltage_100mV =  Max_Voltage_100mV&0b00000000000000000000000111111111;
	  DPM_USER_DEBUG_TRACE(PortNum, "EPR - max voltage: %lu mV", (Max_Voltage_100mV*100));
  }
  break;

 

SPR checking:

case USBPD_CORE_DATATYPE_RCV_SRC_PDO:       /*!< Storage of Received Source PDO values        */
  {
	  DPM_USER_DEBUG_TRACE(PortNum, "Received: %lu bytes", Size);
	  PDO_Max_Number = Size/4; //każdy PDO to 4 bajty
	  if(Size==0U || Size%4U != 0U)
	  {
		  DPM_USER_DEBUG_TRACE(PortNum, "Invalid size - run fixed PDO");
		  If_APDO = 0U;
		  break;
	  }
	  for(uint8_t a=0; a<PDO_Max_Number; a++)
	  {
		  PDO_1=0;
		  PDO_2=0;
		  PDO_3=0;
		  PDO_4=0;
		  PDO=0;
		  PDO_1=(uint32_t)Ptr[a*4U+0U]<<0;
		  PDO_2=(uint32_t)Ptr[a*4U+1U]<<8;
		  PDO_3=(uint32_t)Ptr[a*4U+2U]<<16;
		  PDO_4=(uint32_t)Ptr[a*4U+3U]<<24;
		  PDO=PDO_1|PDO_2|PDO_3|PDO_4;
		  //DPM_USER_DEBUG_TRACE(PortNum, "PDO[%u] = 0x%08lX", a+1, PDO);
		  if((PDO&0b11000000000000000000000000000000UL)!=0b11000000000000000000000000000000UL)
		  {
			  uint32_t Fallback_Voltage=0;
			  Fallback_Voltage=(PDO>>10);
			  Fallback_Voltage=Fallback_Voltage&0b00000000000000000000001111111111;
			  Fallback_Voltage=Fallback_Voltage*50; //napięcie w mV
			  Fallback_Current=PDO&0b00000000000000000000001111111111;
			  Fallback_Current=Fallback_Current*10; //prąd w mA
			  Max_Power[a+1]=Fallback_Voltage*Fallback_Current/1000000;
			  DPM_USER_DEBUG_TRACE(PortNum, "PDO[%u] = %lu mV, %lu mA, %lu W" , a+1, Fallback_Voltage, Fallback_Current, Max_Power[a+1]);
			  if(Fallback_Voltage==20000)
			  {
				  Fallback_PDO=a+1;
				  Fallback_Current = Fallback_Current/10;
				  If_APDO = 0U;
			  }
		  }
		  if((PDO&0b11000000000000000000000000000000UL)==0b11000000000000000000000000000000UL)
		  {
			  uint32_t Max_Voltage_100mV=(PDO>>17);
			  Max_Voltage_100mV =  Max_Voltage_100mV&0b00000000000000000000000111111111;
			  DPM_USER_DEBUG_TRACE(PortNum, "APDO [%u] - max voltage: %lu mV", a+1, (Max_Voltage_100mV*100));
			  if(Max_Voltage_100mV>=Requested_Voltage)
			  {
				  Requested_APDO=a+1;
				  //If_APDO = 1U;
			  }
		  }
	  }
  }
    break;

How to access to full data with all EPR PDOs and APDOs? I have no DPM_Ports.

Best regards

0 Kudos
FBL
ST Employee

‎2026-04-10 10:01 AM

Hi @Jaroslaw_T 

Sorry for not getting back to you sooner. I will clarify this part in the article. Chucking is mandatory in EPR mode in PD3.1;

Now in your case I'm suspecting your handling of extended/chunked messages; can you test with the following source example. Here is my HW setup:

FBL_0-1775840365486.png

 

For my case, to store received SRC EPR PDOs

case USBPD_CORE_DATATYPE_RCV_SRC_PDO_EPR:
  if (Size <= (USBPD_MAX_NB_PDO * 4))
  {
    uint8_t *pdo;
    DPM_Ports[PortNum].DPM_NumberOfRcvSRCEPRPDO = (Size / 4);
    for (index = 0; index < (Size / 4); index++)
    {
      pdo = (uint8_t *)&DPM_Ports[PortNum].DPM_ListOfRcvSRCEPRPDO[index];
      memcpy(pdo, Ptr + index * 4U, 4U);
    }
  }
  break;

 Can you replace your source and attach it to the Sink with the proposed setup?

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Best regards,
FBL
SRC_EPR.zip
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Jaroslaw_T
Associate III

‎2026-04-19 10:06 PM - edited ‎2026-04-22 4:54 AM

Thank You

Unfortunately I have only setup for SINK. For my solution I have my own PCB with STM32G071KBT6 uC. Also I have no DPM_Ports. In USBPD_CORE_DATATYPE_RCV_SRC_PDO_EPR I have only 4 bytes of data.

 

Best regards

Jaroslaw

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FBL
ST Employee

‎2026-04-20 7:23 AM

Thanks for the clarification @Jaroslaw_T .

Can you verify whether the source used advertises EPR capabilities using chunked or unchunked extended messages?

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Best regards,
FBL
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