M66596FP datasheet(78/131 Pages) RENESAS

78 / 131 page

M66596FP/WG

rev .1.00

2006.3.14

page 78 of 127

3.4.1.3 Buffer areas

Table 3.15 shows the FIFO buffer memory map of the controller. The buffer memory has special fixed areas to

which pipes are assigned in advance, and user areas that can be set by the user. The buffer for the DCP is a

special fixed area that is used both for control read transfers and control write transfers. The PIPE6-7 area is

assigned in advance, but the area for pipes that are not being used can be assigned to PIPE1-5 as a user area.

The settings should ensure that the areas of the various pipes do not overlap. Also, the buffer size should not be

specified using a value that is less than the maximum packet size.

Table 3.15 Buffer memory map

Buffer memory no.

Buffer size

Pipe setting

Note

0 – 3

256 bytes

DCP special fixed area

Single buffer, continuous transfers

enabled

64 bytes

Fixed area for PIPE6

Single buffer

64 bytes

Fixed area for PIPE7

Single buffer

6 – 4F

4736 bytes

PIPE1-5 user area

Double buffer can be set, continuous

transfers enabled

3.4.1.4 Auto Buffer Clear mode function

With this controller, all of the received data packets are discard if the ACLRM bit of the PIPExCTR register is

set to “1”. If a normal data packet has been received, however, the ACK response is returned to the host

controller. This function can be set only in the buffer memory reading direction.

Also, if the ACLRM bit is set to “1” and then to “0”, the buffer memory of the pertinent pipe can be cleared

regardless of the access direction. An access cycle of at least 100 ns is required between “ACLRM=1” and

“ACLRM=0”.

3.4.1.5 Buffer memory specifications (single / double setting)

Either a single or double buffer can be selected for PIPE1-5, using the DBLB bit of the PIPExCFG register. The

double buffer is a function that assigns two memory areas specified with the BUFSIZE bit of the PIPEBUF

64 Byte

128 Byte

BUFSIZE=0,

DBLB=0

BUFIZE=0,

DBLB=1

BUFSIZE=1,

DBLB=0

Buffer memory

PIPEBUF reg

Figure 3.20 Example of buffer memory settings

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