Maxim Integrated MAX32600, User Manual, Page: 322 / 687

MAX32600 User’s Guide Communication Peripherals 7.4 USB Device Interface
– Enable for IN or OUT data transfers, ep_int_en
– Enable for NAK handshakes sent to host ep_nak_en
• Endpoint STALL status ep_stall
• Send a STALL to host for status stage ep_st_stall
• Send an ACK to the host for status stage ep_st_ack
7.4.3.2 Endpoint Buffer Descriptor
The endpoint buffer descriptor is used as a communication port between the application firmware and the SIE in system memory. The endpoint buffer descriptor
starting address is specified by the USB endpoint descriptor base address register
USB_EP_BASE.ep_base .
The endpoint data toggle value and the buffer are maintained internally by the SIE. The data toggle value is initialized to DATA0 upon USB reset. The buffer will also
be reset to buffer 0 upon USB reset. When an endpoint is double-buffered, the SIE will use the two buffers in ping-pong fashion. Firmware can reset the active data
buffer by writing 1 to
ep_dt .
Figure 7.9: USB Endpoint Buffer Descriptor Memory
Rev.1.3 April 2015 Maxim Integrated Page 304