FT121T-U Datasheet, PDF (29/46 Pages) Future Technology Devices International Ltd. – Future Technology Devices International Ltd.

Document No.: FT_000648
FT121 ENHANCED USB DEVICE CONTROLLER WITH SPI SLAVE IC
Datasheet Version 1.2
Clearance No.: FTDI# 312
Bit
Symbol
Reset
Description
7 Endpoint Stalled
0
Table 6.16 Endpoint Buffer Status Register
0: endpoint is not stalled
1: endpoint is stalled
6.3.5 Read Buffer
Command
Data
: E0h
: Read multiple bytes
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
: F0h
: Write multiple bytes
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
: F2h
: None
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 : FAh
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