lpcware

LPC1347 USB ROM driver maximum number of EPs

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by nidalpres on Sun Feb 15 22:11:29 MST 2015
Does anyone know what is the maximum number of EPs supported by LPC1347 USB ROM driver?

Physical USB device controller on LPC1347 supports up to 10 physical endpoints which would translate into 5 logical EPs (5 IN + 5 OUT EPs = 10 physical EPs).

Section 10.4.2 in UM lists those 5 logical EPs and I can see that I can have 1 controll (EP0) with 64 byte packet and 4 interrupt/bulk/isochronous with 64/1023 byte packets.

More specifically, when I set parameter max_num_ep of USBD_API_INIT_PARAM am I setting it to the number of logical endpoints or number of physical endpoints my app is using?

app_usbd_cfg.h which comes with LPCOpen USB ROM examples for LPC1347 has USB_MAX_EP_NUM defined to be 5 and that corresponds to maximum number of logical EPs.
USB examples code nowhere explicitly distinguishes between logical and physical EPs, which might be obvious to the ones who wrote the code but it is far from obvious for someone just starting to make sense of USB ROM API.

Thanks for any answer!

N.

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