DAPv1 bundled with DAPv2 has compatibility issues

[elfmimi]

HID interface of DAPLink may not functioning as expected when bulk interface is also present.
It seems there are more than one pattern of behaviors.
I've analyzed these two out of many.

• firmware-0257-798b9e73/gcc/0257_lpc11u35__0x0000.hex
  HID interface does not have any endpoint, because of endpoint shortage.
  Host must use SET_REPORT and GET_REPORT to interact with this.
  Not many software is aware of this kind of configuration.
  Even Linux won't bind hid driver for this device.

• firmware-0257-798b9e73/gcc/0257_lpc55s69__0x10000.hex
  HID interface has both IN and OUT endpoints.
  Despite having OUT endpoint it will get stuck if try to use it.
  Host must use SET_REPORT to workaround the problem.
  Solved with Fix HID interface of LPC55xx HIC #917

[mbrossard]

LPC55S69 HIC fix has been merged. lpc11u35_if is the only project using the lpc11u35 HIC that has bulk interface. There might be 3 simple solutions:

• Remove bulk interface from lpc11u35_if.
• Remove HID interface from lpc11u35_if.
• Remove bulk interface from lpc11u35_if and add lpc11u35_bulk_if with bulk (instead of HID) interface.

[mbrossard]

I tried creating a project with bulk interface but without HID interface and it did not work, so as a first step #920 changes lpc11u35_if to be HID-only, like all other lpc11u35-based projects.

[elfmimi]

I don't yet know why, but this must be the cause bulk interface without HID interface is failing.

DAPLink/source/hic_hal/nxp/lpc11u35/DAP_config.h

Lines 97 to 101 in 8dff8e0

	#ifndef HID_ENDPOINT //HID end points currently set limits to 64
	#define DAP_PACKET_SIZE 512 ///< Specifies Packet Size in bytes.
	#else
	#define DAP_PACKET_SIZE 64 ///< Specifies Packet Size in bytes.
	#endif

Try changing it to 64 , then it should work fine.

[mbrossard]

Looking at the USB configuration it seems all interefaces are limited to 64 bytes:

$ grep WMAXPACKETSIZE source/hic_hal/nxp/lpc11u35/usb_config.c | grep -v _HS_
#define USBD_HID_WMAXPACKETSIZE     64
#define USBD_MSC_WMAXPACKETSIZE     64
#define USBD_ADC_WMAXPACKETSIZE     64
#define USBD_CDC_ACM_WMAXPACKETSIZE     16
#define USBD_CDC_ACM_WMAXPACKETSIZE1    64
#define USBD_BULK_WMAXPACKETSIZE     64
[...]

I took your advice in https://github.com/mbrossard/DAPLink/tree/pr/lpc11u35_if_bulk and it seems to work.

[eleenest]

Just wondering if this issue is only for the lpc11u35_if (maybe a smaller number of hw endpoints available on this MCU?), or if other HICs with a bulk interface are also affected

(looks like a total of 12 interfaces with - records/usb/usb-bulk.yaml in projects.yaml)?

Eric

[mbrossard]

Just wondering if this issue is only for the lpc11u35_if (maybe a smaller number of hw endpoints available on this MCU?), or if other HICs with a bulk interface are also affected

(looks like a total of 12 interfaces with - records/usb/usb-bulk.yaml in projects.yaml)?

I think so. The LPC11U35 "[s]upports 10 physical (5 logical) endpoints including one control endpoint" (https://www.nxp.com/docs/en/data-sheet/LPC11U3X.pdf). We should probably document the number of end-points each HIC has.

[mbrossard]

I checked and documented [df8e414], it seems the only other that might be problematic are the MAX3262x.