39.15.2 Packet Size
Original offset 0x04 & 0x14
| Name: | PCKSIZE |
| Offset: | 0x04 |
| Reset: | 0xXXXXXXXX |
| Property: | NA |
| 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 endpoint.
When enabled, the USB module will manage the ZLP handshake by hardware. This bit is for IN endpoints only. When disabled the handshake should 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] Endpoint size
Bits 27:14 – MULTI_PACKET_SIZE[13:0] Multiple Packet Size
These bits define the 14-bit value that is used for multi-packet transfers.
For IN endpoints, 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 endpoints, 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 is used for the byte count.
For IN endpoints, BYTE_COUNT holds the number of bytes to be sent in the next IN transaction.
For OUT endpoint or SETUP endpoints, BYTE_COUNT holds the number of bytes received upon the last OUT or SETUP transaction.