STM32G071 UCPD library bug or my bad?

[JChau]

Hello there, I have a custom board with STM32G071CB for USB Type C PD Source, dual port, RTOS, configured with CubeMX 5.3.0, after writing code on usbpd_dpm_user.c and start debugging, I suspected there are 2+1 strange behavior so I hope somebody can give me some insights why are these happening:

1. in the code USBPD_SettingsTypeDef.CAD_DefaultResistor is set to 0x00u, from datasheet I am expecting UCPDx.CR.ANASUBMODE should be 1 but what I got from the debugger is 3.
2. with UCPDx.CR.ANASUBMODE set to 3, UCPDx.SR.TYPEC_VSTATE_CC2 is always 1, even though the type-c connector is n.c.! modified UCPDx.CR.ANASUBMODE to 1 fixed everything (i.e. correct behavior for UCPDx cable detection).
3. in USBPD_DPM_GetDataInfo I programmed like this:

switch (DataId)
{
  /* Case Port Source PDO Data information */
  case USBPD_CORE_DATATYPE_SRC_PDO :
  *(uint32_t*)(Ptr) = 0x14019032;
  *Size = 4;
  break;
}

I expected this will send a 5V, 500mA fixed source pdo to my usb-pd packet sniffer, that should be

611332900114

, but what i get is

6103

so I guess something in between my code and the wire filtered my PDO? What's wrong with my code?

[Dominique · Accepted solution]

​Hi John,

Question 1 : the parameter USBPD_SettingsTypeDef.CAD_DefaultResistor is the right place to set the source resistor unfortunately there is a bug inside the G0 device which don't care about the value coming from setting structure.

The correction do perform is the following : file usbpd_cad_hw_if.c function CAD_Init replace the lines

void CAD_Init(uint8_t PortNum, USBPD_SettingsTypeDef *pSettings, USBPD_ParamsTypeDef *pParams,  void (*WakeUp)(void))
{
....
/*  Replace */
//  Ports[PortNum].params = pParams;
// #ifndef _VALID_RP
// #define _VALID_RP vRp_3_0A
// #endif
// Ports[PortNum].params->RpResistor = _VALID_RP;
//  Ports[PortNum].settings = pSettings;
 
/* by   */
Ports[PortNum].params = pParams;
Ports[PortNum].settings = pSettings;
Ports[PortNum].params->RpResistor = Ports[PortNum].settings->CAD_DefaultResistor;

The range of the value for CAD_DefaultResistor are :

#define vRp_Default  0x00u   /*!< Default USB Power  */                 ie ANASUBMODE = 1
 
#define vRp_1_5A       0x01u   /*!< USB Type-C Current @ 1.5 A  */   ie ANASUBMODE = 2
 
#define vRp_3_0A       0x02u   /*!< USB Type-C Current @ 3 A  */      ie ANASUBMODE = 3
 

Please have a lock at function void USBPDM1_AssertRp(uint8_t PortNum) to see the conversion mechanism

Question2 ; this is really strange because for any value of anasubmode a source without cable plug shall return UCPDx.SR.TYPEC_VSTATE_CC2  = UCPDx.SR.TYPEC_VSTATE_CC2 = 2 which means nothing connected. Please could you confirm if the DEAD BATTERY PIN are connected to ground and setup in analog mode ? (DBCC1 and DBCC2)

Question3 : the variable is not necessary 32 bits aligned so you must avoid cast on uint32_t to write it. So we recommend to use a memcpy or the code bellow to avoid more optimized.

  case USBPD_CORE_DATATYPE_SRC_PDO :
//    *(uint32_t*)(Ptr) = 0x14019032;
    Ptr[0] = 0x32;
    Ptr[1] = 0x90;
    Ptr[2] = 0x01;
    Ptr[3] = 0x14;
    *Size = 4;
    break;

I hope my reply will be helpful

BR

[JChau]

Thank you a lot for your reply!

1. Yes that solution fixed the problem, but I guess until a patch to the USBPD library arrives I have to make this change every time after I touched STM32CubeMX...
2. Yes I confirm for both UCPD1 and UCPD2, DBCC1 and DBCC2 is both tied to ground, GPIOA.MODER8 and MODER9 is 0x3 so it should be analog, same situation for UCPD2. Also I tested with ANASUBMODE = 0, 1, 2 and all are performed as expected, only ANASUBMODE = 3 have this problem. For your reference I powered the digital part of my board at 1.8V, just to say so because this seems related to analog voltage,
3. i do fixed the problem using memcpy as ST's demo software, but that gets me confused because I can see Ptr is actually 32bit aligned... anyway it's fixed.

[Dominique]

Hi John

About the question 2, you must take care about the operating condition (see chapter 5.3.23 of the STM32G071CB datasheet)

BR

Dominique

[JChau]

Hi Dominque

Yes I do take notice and asked our hardware guy to bridge the mcu to 3.3V, because we already noticed another problem that not even GoodCRC is sent from any device, so we checked hardware and the upper bound voltage of CC line is only 0.74V, much lower than requried 1.04-1.2V per PD specification.

Anyway, I can confirm that raising the voltage of VDD to 3.3V solved my question 2, but we still don't get any GoodCRC just for your interest :(

Thank you very much for your help anyway!

[Dominique]

Hi John,

This issue could be link with the system clock please could you share the sytem clock configuration ? to make working UCPD, HSI clock shall be enabled.

To check if the problem is linked with the system clock please could use the settings from our G0 demo

BR

Dominique

[JChau]

Hi Dominque,

Attached is the settings from STM32CubeMX, from what I can see it should be the same as G0 demo except PLLN/PLLR, but final clocks are the same

I am now out of office but my final test today is connecting the prototype to my Nexus 6P phone and the phone do says "Quick Charging", but because the only PDO now is 5V 500mA I don't know why "Quick Charging" is displayed:downcast_face_with_sweat: I hope that's just because it did recognized a PD source and if that's the case I can assume my case solved and move on to the other parts of the system.

[Dominique]

Hi John

Please could you send me the USB-PD trace ? i could help you to analyse if there is an issue.

FYI, our software solution embedded is own trace system which could be a great help to analyse USB-PD issue. So i recommend you to enable it, this could be done through Cube-MX (enable the utilities TRACER_EMB and tick the box "Tracer Source (TRACER_EMB)"

And you shall use the UCPD Monitor tools to catch the trace

Interesting link for you

1. Cube Monitor tools : https://www.st.com/en/development-tools/stm32cubemonucpd.html
2. USB-PD user manual : https://www.st.com/content/ccc/resource/technical/document/user_manual/group1/aa/15/14/5d/f5/b8/4a/fc/DM00598101/files/DM00598101.pdf/jcr:content/translations/en.DM00598101.pdf

BR

Dominique

[JChau]

Hi Dominique,

Yes, we do enabled tracer_emb from the start, unfortunately the board 3.3V buck failed (possibility due to all those mods on the board :( ) and our hardware guy is fixing it, so until the board work again there is nothing for me to do right now.

I do read your manual, also docs from USB.org, and even other guys source code for comparison, I have to say the USB-PD library is quite complex and take some time to familiar, functions keep calling here and there and together with RTOS the code size is much larger than we had think of (We love to work directly with registers 🙂 ).

But again thank you a lot for your help! You are so kind and helpful!

[JChau]

btw please let me ask here if we can output custom messages to tracer_emb for our board debugging purpose? will UCPD_Monitor output custom debug messages? And can I set the baud rate to lower rate like 115200?