Renesas M16C Series User Manual page 77

M30240 Group
1.2.18.4.17 USB Endpoint x OUT MAXP Register
The USB Endpoint x OUT MAXP Register, shown in Figure 1.50, indicates the maximum packet size (MAXP)
of an Endpoint x OUT packet. The default values for endpoints 1-4 are 0 bytes. The setting of this register also
affects the configuration of single/dual packet operation. When MAXP > 1/2 of the FIFO size, single packet is
set. When MAXP <= 1/2 of the FIFO size, dual packet mode is set.
USB Endpoint x OUT MAXP Register
b7 b6 b5 b4
Figure 1.50: USB Endpoint x OUT MAXP
1.2.18.4.18 USB Endpoint x OUT Write Count Register
The USB Endpoint x OUT Write Count (WRT CNT) Register, shown in Figure 1.51, contains the number of
bytes of the current data set in the OUT FIFO. The USB FCU sets the value in the Write Count Register after
having successfully received a packet of data from the host. The CPU reads the register to determine the number
of bytes to be read from the FIFO.
USB Endpoint x OUT Write Count Register
b7 b6 b5 b4
Figure 1.51: USB Endpoint x OUT WRT CNT
1.2.18.4.19 USB Endpoint x FIFO Register
The USB Endpoint x FIFO Register, shown in Figure 1.52 is the USB IN (transmit) and OUT (receive) FIFO
data register. The CPU writes data to this register for the corresponding Endpoint IN FIFO and reads data from
this register for the corresponding Endpoint OUT FIFO.
USB Endpoint x FIFO Register
b7 b6 b5 b4
Figure 1.52: USB Endpoint x FIFO Register
Rev.1.00 Sep 24, 2003 Page 59 of 360
b3 b2 b1 b0
Symbol
EPiOMP (i = 1-4)
Bit symbol
Maximum packet size
OMAXP0
(MAXP) of Endpoint x
to
OUT packet.
OMAXP7
b3 b2 b1 b0
Symbol
EPiWC (i = 1-4)
Bit symbol Bit name
W_CNT0
Receive Byte Count
to
W_CNT7
b3 b2 b1 b0
Symbol
EPi (i = 0-4) 0338
Bit symbol Bit name
DATA_0
Endpoint x IN/OUT FIFO
to
DATA_7
Address
031C 0324 032C 0334
16, 16, 16, 16
Function
Bit name
For endpoints that support smaller
FIFO size, unused bits are not
implemented, (always write "0" to
these bits).
Address
031D 0325 032D 0335
16, 16, 16, 16
Function
Address
0339 033A 033B 033C
16, 16, 16, 16, 16
Function
Universal Serial Bus
When reset
00
16
R W
When reset
00
16
R W
X
When reset
Indeterminate
R W
O