![](http://datasheet.mmic.net.cn/120000/ML66525-XXTB_datasheet_3559839/ML66525-XXTB_14.png)
Contents - 11
16.3.1
External Program Memory Access .......................................................................... 16-3
16.3.2
External Data Memory Access................................................................................. 16-4
16.4 External Memory Access Timing .................................................................................... 16-5
16.4.1
External Program Memory Access Timing.............................................................. 16-5
16.4.2
External Data Memory Access Timing.................................................................... 16-6
16.4.3
On the P3_2/RDn Pin............................................................................................... 16-8
16.5 Notes Regarding Usage of Bus Port Function.................................................................. 16-9
16.5.1
Dummy Read Strobe Output.................................................................................... 16-9
16.5.2
External Bus Access Timing.................................................................................. 16-11
Chapter 17
USB Control Function
17.1 Overview.......................................................................................................................... 17-1
17.2 Features ............................................................................................................................ 17-1
17.3 Functional Descriptions ................................................................................................... 17-2
17.3.1
USB Interface........................................................................................................... 17-2
17.3.2
USB Transfer Modes ............................................................................................... 17-2
17.3.3
Endpoints and FIFOs ............................................................................................... 17-3
17.3.4
Operation of Control Transfer.................................................................................. 17-4
17.3.5
Data Packet Transmission and Reception Procedure During Bulk Transfer
and Interrupt Transfer Modes................................................................................... 17-5
17.3.6
Data Packet Transmission and Reception Procedure During Isochronous
Transfer Mode.......................................................................................................... 17-6
17.3.7
Packets and Packet Sizes.......................................................................................... 17-7
17.3.8
Interrupts .................................................................................................................. 17-8
17.3.9
Internal DMA (Direct Memory Access) ................................................................ 17-15
17.3.10 Power-down ........................................................................................................... 17-15
17.3.11 Operation of 2-Layer Structure FIFO During Bulk Transfer ................................. 17-16
17.3.12 Error Processing and Retry Operation ................................................................... 17-18
17.3.13 D+ Pull-up Control ................................................................................................ 17-19
17.4 Registers for USB Control Functions............................................................................. 17-20
17.4.1
Description of Registers for USB Control Functions............................................. 17-22
(1)
EP0 transmit FIFO (EP0TXFIFO) ......................................................................... 17-22
(2)
EP0 receive FIFO (EP0RXFIFO) .......................................................................... 17-22
(3)
EP1 FIFO (EP1FIFO) ............................................................................................ 17-23
(4)
EP2 FIFO (EP2FIFO) ............................................................................................ 17-23
(5)
EP3 FIFO (EP3FIFO) ............................................................................................ 17-24
(6)
EP4 FIFO (EP4FIFO) ............................................................................................ 17-24
(7)
EP5 FIFO (EP5FIFO) ............................................................................................ 17-25