upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 382

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
During bulk transfer (OUT), more data may be transmitted from the host than expected by the system.
µ
Endpoint2 for bulk transfer (OUT) of the
PD78F0730 consist of two 64-byte buffers so that NAK responses
are suppressed as much as possible and data can be read from the CPU side even while the bus side is being
accessed as the transfer rate of the USB bus increases. Consequently, if the host sends more data than
expected by the system, up to 128 bytes of extra data may be automatically received in the worst case. In this
case, change the control flow from that of the normal processing of Endpoint2 to the flow illustrated below
when the quantity of data expected by the system has decreased to two packets.
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Preliminary User’s Manual U19014EJ1V0UD