Packet Size
Name:
PCKSIZE
Offset:
0x04 & 0x14
Reset:
0xxxxxxxx
Access:
NA
Bit3130292827262524
AUTO_ZLPSIZE[2:0]MULTI_PACKET_SIZE[13:10]
AccessR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000
Bit2322212019181716
MULTI_PACKET_SIZE[9:2]
AccessR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000
Bit15141312111098
MULTI_PACKET_SIZE[1:0]BYTE_COUNT[5:0]
AccessR/WR/WR/WR/WR/WR/WR/WR/W
Reset00000000
Bit76543210
Access
Reset

Bit 31 – AUTO_ZLP: Automatic Zero Length Packet

Automatic Zero Length Packet

This bit defines the automatic Zero Length Packet mode of the pipe.

When enabled, the USB module will manage the ZLP handshake by hardware. This bit is for OUT pipes only. When disabled the handshake should be managed by firmware.

ValueDescription
0 Automatic Zero Length Packet is disabled.
1 Automatic Zero Length Packet is enabled.

Bits 30:28 – SIZE[2:0]: Pipe size

Pipe size

These bits contains the size of the pipe.

Theses bits are cleared upon sending a USB reset.

SIZE[2:0] Description
0x0 8 Byte
0x1 16 Byte
0x2 32 Byte
0x3 64 Byte
0x4 128 Byte(1)
0x5 256 Byte(1)
0x6 512 Byte(1)
0x7 1024 Byte in HS mode(1)

1023 Byte in FS mode(1)

1. For Isochronous pipe only.

Bits 27:14 – MULTI_PACKET_SIZE[13:0]: Multi Packet IN or OUT size

Multi Packet IN or OUT size

These bits define the 14-bit value that is used for multi-packet transfers.

For IN pipes, MULTI_PACKET_SIZE holds the total number of bytes sent. MULTI_PACKET_SIZE should be written to zero when setting up a new transfer.

For OUT pipes, MULTI_PACKET_SIZE holds the total data size for the complete transfer. This value must be a multiple of the maximum packet size.

Bits 13:8 – BYTE_COUNT[5:0]: Byte Count

Byte Count

These bits define the 14-bit value that contains number of bytes sent in the last OUT or SETUP transaction for an OUT pipe, or of the number of bytes to be received in the next IN transaction for an input pipe.