FT121Q-R FTDI, FT121Q-R Datasheet - Page 28

• Manufacturer Part Number: FT121Q-R
• Description: USB Interface IC USB CONTROLLER W/SPI SLAVE IC
• Manufacturer: FTDI

Specifications of FT121Q-R

• Rohs: yes
• Product: USB 2.0
• Interface Type: SPI, USB
• Operating Supply Voltage: 4 V to 5.5 V
• Operating Supply Current: 3.9 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-16
• Minimum Operating Temperature: - 40 C

Table 6-16 Endpoint Buffer Status Register
6.3.5 Read Buffer
Command
Data
The Read Buffer command is used to read the received packet from the selected endpoint OUT buffer.
The data in the endpoint buffer is organized as follows:
byte 0: length of payload packet, MSB(for default mode this byte is ignored)
byte 1: length of payload packet, LSB
byte 2: Payload packet byte 1
byte 3: Payload packet byte 2
…
byte n+1: Payload packet byte n (n = packet length)
6.3.6 Write Buffer
Command
Data
The Write Buffer command is used to write payload packet to the selected endpoint IN buffer.
The data must be organized in the same way as described in the Read Buffer command. For default mode
byte 0 should always be set to 00h.
6.3.7 Clear Buffer
Command
Data
Followed by Read Buffer command, the Clear Buffer command should be issued after all data has been
read out from the endpoint buffer. This is to free the buffer to receive next packet from USB host.
6.3.8 Validate Buffer
Command
Bit
7
Endpoint Stalled
: E0h
: Read multiple bytes
: F0h
: Write multiple bytes
: F2h
: None
: FAh
Symbol
Copyright © 2012 Future Technology Devices International Limited
FT121 ENHANCED USB DEVICE CONTROLLER WITH SPI SLAVE IC
Reset
0
0: endpoint is not stalled
1: endpoint is stalled
Description
Document No.: FT_000648
Clearance No.: FTDI#
Datasheet Version 1.0
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