FT221XQ-T FTDI, FT221XQ-T Datasheet - Page 15

• Manufacturer Part Number: FT221XQ-T
• Description: USB Interface IC USB to 8 bit SPI / FT1248 IC QFN-20
• Manufacturer: FTDI

Specifications of FT221XQ-T

• Rohs: yes
• Tradename: X-Chip

Figure 5.2: FT1248 Command Structure
5.2 Supported Commands on the FT1248 Interface
The FT1248 interface can accept and decode up to 16 unique commands. At this time only 9 unique
commands are implemented as shown below.
Command
write
read
read modem status
write modem status
write buffer flush
1-bit Bus
2-bit Bus
4-bit Bus
8-bit Bus
Width
Width
Width
Width
CMD[3]
CMD[3]
CMD[3]
CMD[3]
CMD[3]
LSB
0
0
0
0
0
Copyright © 2013 Future Technology Devices International Limited
BWID 2-bit BWID 4-bit
Identifier
0x00
0x01
0x02
0x03
0x04
X
X
X
1
1
0
1
1
1
X
X
X
2
2
2
0
2
2
Description
Write request command
Read request command
Read modem status command, users may wish to emulate
modem status control. A RMS command returns status bits
RTS and DTR
Write modem status command, users may wish to emulate
modem status control. A WMS command allows users to set
status bits: DCD, RI, DSR, CTS
Write buffer flush request – This command is used to indicate
to the FT1248 slave that its write buffers should be flushed
rather than wait for any latency timers to expire. If this
command is received the FT1248 block will flag the upstream
controllers (USB FIFOs etc) to flush their write buffers
regardless of what content is present in the FT1248 write
CMD[2]
CMD[2]
CMD[2]
CMD[2]
CMD[2]
3
3
3
3
3
Document No.: FT_000630 Clearance No.: FTDI# 263
BWID 8-bit
X
X
X
4
4
4
4
0
4
CMD[1]
CMD[1]
CMD[1]
CMD[1]
CMD[1]
5
5
5
5
5
CMD[0]
CMD[0]
CMD[0]
CMD[0]
CMD[0]
6
6
6
6
6
Version 1.2
MSB
X
X
X
X
X
7
7
7
7
7
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