Read sequence:
Write the address of USB register to be accessed into USB_ADDR
Write 1 into USB_CTL.URD
Read data from USB_DO
Write 0 into USB_CTL.URD
Whenever USB engine finished a transaction, it will generate an interrupt to acknowledge CPU.
User can get information about the transaction through the above sequence. When USB engine
received a reset event from host, it will reset itself and generate an interrupt. When USB engine
received a resume event from host (the device is in suspend mode), it will generate a signal to
enable oscillator. If host and the device are both in suspend mode, a falling edge on P3 can
wake the device and firmware com trigger a remote wakeup event from usb engine to host.
USB SFR Category - Descriptions Summary
Mnemonic
DCON
Address
01H
USB Device SFRs
Device Control
Register
Function Address
Register
Function Power
Control Register
USB Interrupt
System SFRs
USB Function
Interrupt Enable
Register
USB Function
Interrupt Flag
Register
Description
–
–
–
–
A6
–
–
–
A4
–
–
EP3DIR
PUREN
A1
CONPUEN
A0
FADDR
FPCON
08H
12H
A5
A3
A2
–
FRWU
URST
FRSM
FSUS
Mnemonic
Address
Description
FIE
18H
1AH
–
–
–
–
FRXIE3
FTXIE2
FTXIE1
FRXIE0
FTXIE0
FIFLG
–
–
–
–
FRXD3
–
FTXD2
EFSR
FTXD1
–
FRXD0
EF
FTXD0
–
USB Interrupt
Enable Register
USB Endpoint
SFRs
Endpoint Index
Register
IEN1
10H
Address
31H
Mnemonic
EPINDEX
EPCON*
Description
–
–
–
–
–
–
–
–
–
EPINX1
–
EPINX0
Endpoint Control
Register
21H
RXSTL
TXSTL
RXEPEN
TXEPEN
Receive FIFO
Byte-Count
RXCNT*
26H
–
–
–
–
RXBC3
RXBC2
RXBC1
RXBC0
Register
Receive FIFO
Control Register
Receive FIFO
Data Register
Endpoint Receive
Status Register
Transmit FIFO
Byte-Count
RXCON*
RXDAT*
RXSTAT*
24H
23H
22H
RXCLR
RD7
–
–
RXFFRC
RD4
–
–
RD2
–
–
RD1
–
–
RD0
–
RD6
RD5
RD3
RXSEQ
RXSETUP
STOVW
EDOVW RXSOVW
TXCNT*
36H
–
–
–
–
TXBC3
TXBC2
TXBC1
TXBC0
Register
Transmit FIFO
Control Register
Transmit FIFO
Data Register
Endpoint Transmit
Status Register
TXCON*
TXDAT*
TXSTAT*
34H
33H
32H
TXCLR
TD7
–
TD6
–
–
TD5
–
–
TD4
–
–
–
TD2
–
–
TD1
–
–
TD0
–
TD3
TXSEQ
TXSOVW
18
MPC235 Data Sheet
MEGAWIN
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
