Information

40.4.18 Frame Number Register High (USBx_FRMNUMH)
The Frame Number Register (Low and High) contains an 11-bit value used to compute
the address where the current Buffer Descriptor Table (BDT) resides in system memory.
Addresses: USB0_FRMNUMH is 4007_2000h base + A4h offset = 4007_20A4h
Bit 7 6 5 4 3 2 1 0
Read 0
FRM[10:8]
Write
Reset
0 0 0 0 0 0 0 0
USBx_FRMNUMH field descriptions
Field Description
7–3
Reserved
This read-only field is reserved and always has the value zero.
2–0
FRM[10:8]
This 3-bit field and the 8-bit field in the Frame Number Register Low are used to compute the address
where the current Buffer Descriptor Table (BDT) resides in system memory.
40.4.19 Token Register (USBx_TOKEN)
The Token Register is used to perform USB transactions when in host mode
(HOSTMODEEN=1). When the processor core wishes to execute a USB transaction to a
peripheral, it writes the TOKEN type and endpoint to this register. After this register has
been written, the USB module begins the specified USB transaction to the address
contained in the address register. The processor core should always check that the
TOKEN_BUSY bit in the control register is not set before performing a write to the
Token Register. This ensures token commands are not overwritten before they can be
executed. The address register and endpoint control register 0 are also used when
performing a token command and therefore must also be written before the Token
Register. The address register is used to correctly select the USB peripheral address
transmitted by the token command. The endpoint control register determines the
handshake and retry policies used during the transfer.
Addresses: USB0_TOKEN is 4007_2000h base + A8h offset = 4007_20A8h
Bit 7 6 5 4 3 2 1 0
Read
TOKENPID TOKENENDPT
Write
Reset
0 0 0 0 0 0 0 0
Memory map/Register definitions
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
910 Freescale Semiconductor, Inc.