Renesas M16C Series User Manual page 183

M30245 Group
USB endpoint 0 MAXP register
This register indicates the IN/OUT maximum packet size of endpoint 0.
When a GET_DESCRIPTION request is received from the host CPU, write to this register to change
the IN/OUT maximum packet size value of endpoint 0.
Set the packet size value (8, 16 or 32 bytes) specified by control transfer. The default value is 8 bytes.
The configuration of USB endpoint 0 MAXP register is shown in Figure 2.8.33.
USB Endpoint 0 MAXP register
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(b15)
b7
0 0 0 0 0 0 0 0 0
Figure 2.8.33. USB endpoint 0 MAXP register
USB endpoint 0 OUT write count register
This register contains the number of bytes of the current data set in the OUT FIFO. When the USB
function control unit completes the data packet receive from the host CPU, set the value of this regis-
ter. When one buffer data receive completes, read this register and determine the number of bytes to
be read from OUT FIFO. This register value is not decremented even if the data is read from OUT
FIFO.
When CLR_OUT_BUF_RDY bit of the EP0CSR is set to "1", this register value is cleared to "0".
The configuration of USB endpoint 0 OUT write count register is shown in Figure 2.8.34.
USB Endpoint 0 Write Count register
(b15)
b7
0 0 0 0 0 0 0 0
Figure 2.8.34. USB endpoint 0 OUT write count register
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
(b8)
b0 b7 b0
(b8)
b0 b7 b0
page 174 of 354
Symbol Address
EP0MP 029A
16
Bit Symbol
Bit Name
Maximum packet size
EP0MP6-0
Reserved
Symbol Address
EP0WC 029C
Bit Symbol Bit Name
Receive byte count
EP0WC7-0
Reserved
2. USB function
When reset
0008
16
Function
Set maximum packet size
of EP0 IN/OUT
Must always be "0"
When reset
0000
16 16
Function
The number of bytes of the current
data set in EP0 OUT FIFO
Must always be "0"
R W
O O
O O
R W
O X
O O