
Universal Serial Bus Interface – On-The-Go Module
Freescale Semiconductor
21-61
21.5.3.4.2
Priming Receive Endpoints
Priming receives endpoints identical to priming of transmit endpoints from the point of view of the DCD.
The major difference in the operational model at the device controller is no data movement of the leading
packet data because the data is to be received from the host.
As part of the architecture, the FIFO for the receive endpoints is not partitioned into multiple channels like
the transmit FIFO. Thus, the size of the RX FIFO does not scale with the number of endpoints.
21.5.3.4.3
Interrupt/Bulk Endpoint Operation
The behaviors of the device controller for interrupt and bulk endpoints are identical. All valid IN and OUT
transactions to bulk pipes handshake with a NAK unless the endpoint is primed. After the endpoint is
primed, data delivery commences.
A dTD is retired by the device controller when the packets described in the transfer descriptor are
completed. Each dTD describes N packets to transfer according to the USB variable length transfer
protocol. The formula below and
describe how the device controller computes the number and
length of the packets sent/received by the USB vary according to the total number of bytes and maximum
packet length. See
Section 21.5.2.1.1, “Endpoint Capabilities/Characteristics (Offset = 0x0)
on the ZLT bit.
With zero-length termination (ZLT) cleared:
N = INT(number of bytes/max. packet length) + 1
With zero-length termination (ZLT) set:
N = MAXINT(number of bytes/max. packet length)
NOTE
The MULT field in the dQH must be set to 00 for bulk, interrupt, and control
endpoints.
Table 21-51. Variable Length Transfer Protocol Example (ZLT=0)
Bytes
(dTD)
Max. Packet
Length (dQH)
N
P1
P2
P3
511
256
2
256
255
—
512
256
3
256
256
0
512
512
2
512
0
—
Table 21-52. Variable Length Transfer Protocol Example (ZLT=1)
Bytes
(dTD)
Max. Packet
Length (dQH)
N
P1
P2
P3
511
256
2
256
255
—
512
256
2
256
256
—
512
512
1
512
—
—
MCF5329 Reference Manual, Rev 3
Summary of Contents for MCF5329
Page 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...