AT91RM9200-QI-002 Atmel, AT91RM9200-QI-002 Datasheet - Page 563

• Manufacturer Part Number: AT91RM9200-QI-002
• Description: IC ARM9 MCU 208 PQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91RM9200-QI-002

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: POR
• Number Of I /o: 122
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: ROM
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 208-MQFP, 208-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

Figure 34-8. Data OUT Transfer for Non Ping-pong Endpoints
Using Endpoints With
Ping-pong Attributes
1768I–ATARM–09-Jul-09
RX_DATA_BK0
(USB_CSRx)
FIFO (DPR)
Content
USB Bus
Packets
Data OUT
PID
Host Sends Data Payload
Written by USB Device
Data OUT 1
An interrupt is pending while the flag RX_DATA_BK0 is set. Memory transfer between the USB
device, the FIFO and microcontroller memory can not be done after RX_DATA_BK0 has been
cleared. Otherwise, the USB device would accept the next Data OUT transfer and overwrite the
current Data OUT packet in the FIFO.
During isochronous transfer, using an endpoint with ping-pong attributes is necessary. To be
able to guarantee a constant bandwidth, the microcontroller must read the previous data pay-
load sent by the host, while the current data payload is received by the USB device. Thus two
banks of memory are used. While one is available for the microcontroller, the other one is locked
by the USB device.
Data OUT 1
5. The microcontroller carries out data received from the endpoint’s memory to its mem-
6. The microcontroller notifies the USB device that it has finished the transfer by clearing
7. A new Data OUT packet can be accepted by the USB device.
ory. Data received is available by reading the endpoint’s UDP_FDRx register.
RX_DATA_BK0 in the endpoint’s UDP_CSRx register.
Set by USB Device
ACK
Host Sends the Next Data Payload
Microcontroller Read
PID
Microcontroller Transfers Data
Data OUT 1
Data OUT2
Interrupt Pending
PID
Data OUT2
NAK
PID
Cleared by Firmware,
Data Payload Written in FIFO
Data OUT
PID
Host Resends the Next Data Payload
Written by USB Device
Data OUT 2
Data OUT2
AT91RM9200
ACK
PID
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