Universal Serial Bus (USB)
Am186™CC/CH/CU Microcontrollers User’s Manual
18-33
18.5.13
Software-Related Considerations
■
A data endpoint must be configured with the xEPDEFx register before enabling it with
the EP_EN bit in the xEPCTL register.
■
When the MODE bit field in the xEPDEF3 register is set to 101b (SmartDMA channel,
status stored in the buffer descriptor), a bulk OUT transfer that results in a retransmission
of data by the host due to handshake packet errors produces the following buffer
descriptor field values: STP = 1, ENP = 1, and CRC = 1. The MCNT value in the buffer
descriptor is invalid because setting the CRC bit causes the ERR bit to be set as well.
Also, when the MODE bit field is set to 101b, a bulk or isochronous OUT transfer with a
message size that is an integer multiple of the maximum packet size results in the
following buffer descriptor field values: STP = 1, ENP = 1, and MCNT = 0.
18.6
INITIALIZATION
On both an external and internal reset, the following occurs:
■
All USB interrupts are cleared and masked.
■
The USB peripheral controller reports that it is self-powered (S_POWER bit of the
USBMFR register is set).
■
The interrupt endpoint number is set to 1.
■
The interrupt endpoint FIFO defaults to 16 bytes deep.
■
The interrupt endpoint maximum packet size is set to 16d.
■
The A, B, C, and D endpoints default to OUT direction, bulk type, with a maximum packet
size of 8 bytes.
■
The A and B endpoint FIFOs default to 16 bytes deep.
■
The C and D endpoint FIFOs default to 64 bytes deep.
■
The Isochronous Missed Packet and Full Data Packet interrupts are unmasked.
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...