FT122Q-R FTDI, FT122Q-R Datasheet - Page 21

• Manufacturer Part Number: FT122Q-R
• Description: USB Interface IC USB CONTROLLER W/ PARALLEL BUS IC
• Manufacturer: FTDI

Specifications of FT122Q-R

• Rohs: yes
• Product: USB 2.0
• Interface Type: Parallel
• Operating Supply Voltage: 1.65 V to 3.6 V, 4 V to 5.5 V
• Operating Supply Current: 3.9 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-28
• Minimum Operating Temperature: - 40 C

Table 6-6 Clock Division Factor Register (Byte 2)
6.2.4 Set DMA
Command
Data
5-4
1-0
Bit
Bit
6
7
2
3
4
5
6
Reserved
SET_TO_ONE
SOF-only Interrupt
Mode
DMA Burst
DMA Enable
DMA Direction
Auto Reload
Interrupt Pin Mode
EPI4 Interrupt Enable
: FBh
: Read/Write 1 byte; Read/Write 2 bytes (for Enhanced Mode)
Symbol
Symbol
Copyright © 2012 Future Technology Devices International Limited
FT122 ENHANCED USB DEVICE CONTROLLER WITH PARALLEL
Reset
Reset
0b’00
0b’00
0
0
0
0
0
0
0
Reserved, write to 0
This bit must be set to 1
0: normal operation
1: interrupt will generate on receiving SOF packet only,
regardless the value of the Interrupt Pin Mode bit in DMA
configuration register.
Set the DMA burst size
00: Single cycle mode
01: 4 cycle burst mode
10: 8 cycle burst mode
11: 16 cycle burst mode
Enable DMA operation
0: DMA operation is disabled
1: DMA operation is enabled
FT122 will clear this bit upon EOT_n assertion.
This bit indicates the DMA read or write operation.
0: DMA read. Data read from FT122 OUT buffer to
system memory.
1: DMA write. Data write to FT122 IN buffer from system
memory.
Automatically restart the DMA operation.
0: DMA needs to restart by software
1: DMA will restart automatically after the previous DMA
transfer finishes
0: normal operation. Interrupt will generate if any of the
bit in the interrupt register is set.
1: interrupt will generate upon receiving SOF packet or if
any of the bit in the interrupt register is set.
Interrupt Enable for endpoint index 4. During DMA
operation, EPI4 interrupt should be turned off to avoid
un-necessary interrupt service.
For enhanced mode this bit has no function. EPI4
interrupt is always enabled unless it is selected as a DMA
BUS
Description
Description
Document No.: FT_000647
Clearance No.: FTDI#
IC
Datasheet Version 1.0
313
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