MPC8280 datasheet(829/1386 Pages) FREESCALE

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Universal Serial Bus Controller

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

27-13

Once initialized, the parameter RAM values do not normally need to be accessed by user software. They

should only be modified when no USB activity is in progress.

27.5.4

Endpoint Parameters Block Pointer (EPxPTR)

The endpoint parameter block pointers (EPxPTR) are DPRAM indices to an endpoint’s parameter block.

The parameter block can be allocated to any address that is divisible by 32. The format of the endpoint

pointer registers (EPxPTR) is shown in Figure 27-6.

The map of the endpoint parameter block is shown in Table 27-5.

USB Base + 18

RXUSB_

Data

Word

Rx Data temp

USB Base + 1C

RXUPTR

Half word

Rx microcode return address temp

1 The items in boldface should be initialized by the user before the USB controller is enabled; other values are initialized

by the CP.

Field

Endpoint Index Pointer

—

R/W

Reset

—

Addr

USB base + 0x00 (EP1PTR), 0x02 (EP2PTR), 0x04 (EP3PTR), 0x06 (EP4PTR)

Figure 27-6. Endpoint Pointer Registers (EP

xPTR)

Table 27-5. Endpoint Parameter Block

Offset1

Name2

Width

Description

0x00

RBASE

16 bits

RxBD/TxBD base addresses. Define the starting location in dual-port RAM for the

USB controller’s TxBDs and RxBDs. This provides flexibility in how BDs are

partitioned. Setting W in the last BD in each list determines how many BDs to allocate

for the controller’s send and receive sides. These entries must be initialized before the

controller is enabled. Overlapping USB BD tables with another serial controller’s BDs

causes erratic operation. RBASE and TBASE values should be divisible by 8.

When using the transaction-level interface in host mode, TBASE points to the TrBD

ring, and RBASE is unused.

0x02

TBASE

16 bits

0x04

RFCR

8 bits

Rx/Tx function code. Controls the value to appear on AT[1–3] when the associated

SDMA channel accesses memory and the byte-ordering convention.

0x05

TFCR

8 bits

Table 27-4. USB Parameter RAM Memory Map (continued)

Address

Name1

Width

Description

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