40.15.2 Packet Size
| Name: | PCKSIZE |
| Offset: | 0x04 + n*0x10 [n=0..1] |
| Reset: | 0xXXXXXXX |
| Property: | - |
| 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) |
- 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.