AT83C5136 Atmel Corporation, AT83C5136 Datasheet - Page 110

• Manufacturer Part Number: AT83C5136
• Manufacturer: Atmel Corporation

Specifications of AT83C5136

• Max. Operating Frequency: 32 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 512
• Operating Voltage (vcc): 2.7 to 3.6
• Timers: 4
• Mask Rom (kbytes): 32
• Watchdog: Yes

21.4.4
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AT83C5134/35/36
Bulk/Interrupt IN Transactions in Ping-pong Mode
Figure 21-10. Bulk/Interrupt IN Transactions in Ping-pong Mode
An endpoint will be first enabled and configured before being able to send Bulk or Interrupt
packets.
The firmware will fill the FIFO bank 0 with the data to be sent and set the TXRDY bit in the UEP-
STAX register to allow the USB controller to send the data stored in FIFO at the next IN request
concerning the endpoint. The FIFO banks are automatically switched, and the firmware can
immediately write into the endpoint FIFO bank 1.
When the IN packet concerning the bank 0 has been sent and acknowledged by the Host, the
TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware
will clear the TXCMPL bit before filling the endpoint FIFO bank 0 with new data. The FIFO banks
are then automatically switched.
When the IN packet concerning the bank 1 has been sent and acknowledged by the Host, the
TXCMPL bit is set by the USB controller. This triggers a USB interrupt if enabled. The firmware
will clear the TXCMPL bit before filling the endpoint FIFO bank 1 with new data.
The bank switch is performed by the USB controller each time the TXRDY bit is set by the firm-
ware. Until the TXRDY bit has been set by the firmware for an endpoint bank, the USB controller
will answer a NAK handshake for each IN requests concerning this bank.
Note that in the example above, the firmware clears the Transmit Complete bit (TXCMPL) before
setting the Transmit Ready bit (TXRDY). This is done in order to avoid the firmware to clear at
the same time the TXCMPL bit for bank 0 and the bank 1.
HOST
IN
IN
IN
IN
ACK
ACK
ACK
DATA0 (n Bytes)
DATA1 (m Bytes)
DATA0 (p Bytes)
NACK
UFI
TXCMPL
TXCMPL
Endpoint FIFO Bank 0 - Write Byte 1
Endpoint FIFO Bank 0 - Write Byte 2
Endpoint FIFO Bank 0 - Write Byte n
Endpoint FIFO Bank 1 - Write Byte 1
Endpoint FIFO Bank 1 - Write Byte 2
Endpoint FIFO Bank 1 - Write Byte m
Endpoint FIFO Bank 0 - Write Byte 1
Endpoint FIFO Bank 0 - Write Byte 2
Endpoint FIFO Bank 0 - Write Byte p
Endpoint FIFO Bank 1 - Write Byte 1
C51
Clear TXCMPL
Clear TXCMPL
Set TXRDY
Set TXRDY
Set TXRDY
7683C–USB–11/07