38.15.2 Packet Size


Bit	31	30	29	28	27	26	25	24
	AUTO_ZLP	SIZE[2:0]			MULTI_PACKET_SIZE[13:10]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	x	0	0	x	0	0	0	0


Bit	23	22	21	20	19	18	17	16
	MULTI_PACKET_SIZE[9:2]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
	MULTI_PACKET_SIZE[1:0]		BYTE_COUNT[13:8]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	x	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
	BYTE_COUNT[7:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	x

Bit 31 – AUTO_ZLP 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 must be managed by firmware.

Value	Description
0	Automatic Zero Length Packet is disabled.
1	Automatic Zero Length Packet is enabled.

Bits 30:28 – SIZE[2:0] Pipe size

These bits contains the size of the pipe.

These 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	1023 Byte⁽¹⁾

Note:

For Isochronous pipe only.

Bits 27:14 – MULTI_PACKET_SIZE[13:0] 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 must 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 13:0 – BYTE_COUNT[13:0] 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.

Name:	PCKSIZE
Offset:	0x04 + n*0x10 [n=0..1]
Reset:	0xXXXXXXX
Property:	-