Usb Endpoint 0 Maxp Register; Usb Endpoint 0 Out Write Count Register; Usb Endpoint X In Control/Status Register - Renesas M16C Series User Manual

M30240 Group

3.2.2.12 USB Endpoint 0 MaxP Register

The USB Endpoint 0 MaxP Register indicates the Maximum Packet size (MaxP) of Endpoint 0 (IN/
OUT). This register should be updated when the transmission of the SET_DESCRIPTOR command
is received from the host CPU.
Figure 3.18 shows the structure of USB Endpoint 0 MaxP register.
USB Endpoint 0 MaxP Register
b7 b6 b5 b4 b3 b2
O O
Figure 3.18: USB Endpoint 0 MaxP Register (EP0MP)

3.2.2.13 USB Endpoint 0 OUT Write Count Register

This is the 5-bit register that contains the number of bytes of data written to the endpoint 0 OUT FIFO.
The USB FCU sets the value in the write count register after successfully receiving a data packet from
the host. This register should be referenced when data is read from the OUT FIFO.
Figure 3.19 shows the structure of the USB Endpoint 0 OUT Write Count Register.
USB Endpoint 0 OUT Write Count Register
b7 b6 b5 b4 b3 b2
O O O
Figure 3.19: USB 0 OUT Write Counter Register

3.2.2.14 USB Endpoint X IN Control/Status Register

• The USB Endpoint X IN Control and Status Register contains the control and status information for the
specific IN Endpoint (1-4).
• IN_PKT_RDY Bit
This bit is set to "1" when a data packet is written to the IN FIFO. If AUTO_SET = 1, it automatically
becomes "1" when the MaxP is written to the FIFO. After the transmission of the data packet from the
IN FIFO has ended (after the receipt of the ACK transmission from the host), the USB function control
unit clears this bit to "0".
The IN_PKT_RDY bit is used to confirm the end of the transmission of the data packet. The state of
this bit should be confirmed with the TX_NOT_EPT flag.
Rev.1.00 Sep 24, 2003 Page 304 of 360
b1 b0
Symbol
EP0MP
Bit Symbol
EP0MXP0 to Maximum packet size (MaxP)
EP0MXP5 of Endpoing 0 IN/OUT packet
Reserved
b1 b0
Symbol
EP0WC
Bit Symbol
WCNT0 to
Receive Byte count
WCNT4
Reserved
Address
0313
16
Bit Name Function
Must always be set to "0"
Address
0315
16
Bit Name Function
Must always be set to "0"
Universal Serial Bus
When reset
08
16
R W
O O
O O
When reset
00
16
R W
O X
O X