R8A66597BG RENESAS [Renesas Technology Corp], R8A66597BG Datasheet - Page 136

• Manufacturer Part Number: R8A66597BG
• Description: ASSP (USB2.0 2 Port Host/1 Port Peripheral Controller)
• Manufacturer: RENESAS [Renesas Technology Corp]

R8A66597FP/DFP/BG
3.4.1.5 Buffer Memory Operations (continuous transfer setting)
R e v 1 . 0 1
The CNTMD bit in either the DCPCFG or PIPExCFG register can be used to select the continuous or non-continuous
transfer mode. Selection can be made for pipes 0-5.
The continuous transfer mode sends/receives multiple transactions continuously. When the continuous transfer mode
is selected, data can be transferred up to the buffer size assigned to each pipe, without interrupts to the CPU.
In the continuous send mode, the write data is sent divided into maximum packet sizes. If the send data that is less
than the buffer size (short packets or packets in integral multiples of the maximum packet size that are smaller than the
buffer size), “BVAL=1” must be set after the send data is written.
In the continuous receive mode, the BRDY interrupt is not generated until packets are received up to the buffer size,
the transaction count is completed, or a short packet is received.
Figure 3.15shows a status transition example of the controller’s CNTMD bit and buffer memory.
O c t 1 7 , 2 0 0 8
(3) CNTMD=0, Packet send example (DBLB=0))
(1) CNTMD=0, Packet receive example (DBLB=0)
1 packet of send data
1 packet of receive data
Buffer Memory
Figure 3.15 CNTMD Bit and Buffer Memory Status Transition Example
Unused area
Buffer Memory
Unused area
p a g e 1 3 6 o f 1 8 3
Transition to
send-enabled status
Transition to
read-enabled status
(2) CNTMD=1, Packet receive example (DBLB=0)
(4) CNTMD=1, Packet send example (DBLB=0)
1 packet of receive data
(Maximum Packet Size)
1 packet of receive data
(Maximum Packet Size)
1 packet of receive data
1 packet of receive data
(Maximum Packet Size)
(Maximum Packet Size)
(Maximum Packet Size)
(Maximum Packet Size)
(Maximum Packet Size)
1 packet of send data
1 packet of send data
1 packet of send data
1 packet of send data
Buffer Memory
Buffer Memory
Transition to
send-enabled status
Transition to
read-enabled status