Renesas M16C Series User Manual

Universal Serial Bus
M30240 Group
Rev.1.00 Sep 24, 2003 Page 300 of 360
3.2.2.7 USB Frame Number Registers
These two registers hold the frame number (11 bits) received from the host CPU. They are read only.
Figure 3.13 shows the structures of the USB frame number registers.
Figure 3.13: USB Frame Number Registers (USBSOFL, USBSOFLH)
3.2.2.8 USB ISO Control Register
The USB ISO Control Register contains two bits: ISO_UPD and AUTO_FL. These bits are used to
control endpoints 1-4 during isochronous transfers.
• AUTO_FLUSH Bit
When the ISO bit (INxCSR3) =”1”, the ISO_UPDATE bit =”1”and the AUTO_FLUSH =”1”, the USB
function control unit automatically flushes the oldest data packet within the FIFO if the IN_PKT_RDY
(INxCSR0) =”1” at time of an SOF packet detection.
• ISO_UPDATE Bit
In the case that the ISO_UPDATE bit =”1”, the IN FIFO data is transmitted when the USB function
control unit receives the next IN token from the host CPU.
When the ISO_UPDATE bit =”1” and the ISO bit (INxCSR3) =”1”, the USB function control unit does
not conduct transmission even if an IN token is received from the host CPU; it delays the transmission
until the next SOF
is detected.
Figure 3.14 shows the structure of the ISO Control Register.
Figure 3.14: USB ISO Control Register (USBISOC)
Bit Symbol Bit Name Function R W
FN0 to FN7
Lower 8 bits of the 11-bit
frame number issued with
and SOF token
O X
Symbol
USBSOFL
Address
0306
16
When reset
00
16
USB Frame Number Low Register
b7 b5b6 b4 b3 b2 b1 b0
Bit Symbol Bit Name Function R W
FN8
Reserved
Must always be set to "0"
O X
O O
O O O O O
Symbol
USBSOFH
Address
0307
16
When reset
00
16
USB Frame Number High Register
b7 b5b6 b4 b3 b2 b1 b0
Upper 3 bits of the 11-bit
frame number issued with
an SOF token
FN9
FN10
USB Frame number bit
USB Frame number bit
Bit Symbol Bit Name Function R W
Reserved Must always be set to "0"
O O
O O
O O O O O O
Symbol
USBISOC
Address
0308
16
When reset
00
16
USB ISO Control Register
b7 b5b6 b4 b3 b2 b1 b0
O O
AUTO_FL
ISO_UPD
AUTO FLUSH Bit
ISO-UPDATE Bit
0 : Hardware auto FIFO flush disabled
1 : Hardware auto FIFO flush enabled
0 : ISO_UPDATE disabled
1 : ISO_UPDATE enabled

Renesas M16C Series Specifications

General

Brand	Renesas
Model	M16C Series
Category	Computer Hardware
Language	English