I am using SDK 2.4.1.
/* WORKAROUND for artf44835 ROM driver BUG:
Code clearing STALL bits in endpoint reset routine corrupts memory area
next to the endpoint control data. For example When EP0, EP1_IN, EP1_OUT,
EP2_IN are used we need to specify 3 here. But as a workaround for this
issue specify 4. So that extra EPs control structure acts as padding buffer
to avoid data corruption. Corruption of padding memory doesn’t affect the
usb_param.max_num_ep = 2 + 1;
usb_param.mem_base = (uint32_t)&g_memUsbStack;
usb_param.mem_size = USB_STACK_MEM_SIZE;
I have 3 questions:
I read “For example When EP0, EP1_IN, EP1_OUT, EP2_IN are used we need to specify 3 here” as the value 3 referring to the number of Logical endpoints and NOT physical endpoints. Is this correct?
assuming that the workaround refers to logical endpoints this explains that “2 + 1” because of EP0 and EP1_IN (HID).
why is this workaround missing from other ROM USB Stack based examples ?
For example, rom_dev_audio_bm\sources\audio_main.c\#99 reads:
usb_param.max_num_ep = 2;
2.a) this does not mention WORKAROUND for artf44835?
2.b) The example is using EP0,EP1_IN,EP1_OUT;so shouldn't this be 2+1 as well to address artf44835?
With the discrepancy mentioned above in [2.a], is artf44835 still relevant to LPC546xx or should it be dismissed?