Document No.: FT_000589
FT313H USB2.0 HS Host Controller Datasheet Version 1.1
Clearance No.: FTDI# 318
5.2.7 FRINDEX register (address = 1Ch)
This register is used by the host controller to index into the periodic frame. The register updates very 125
microseconds (one each micro-frame).
Bit
Name
Type
RO
Default value
28’h0
Description
[31:14]
[13:0]
Reserved
FRINDEX
-
Frame Index
R/W
14’b0
This register is used by the host controller to
index the frame into the Periodic Frame List. It
updates every 125 microseconds. This register
cannot be written unless the host controller is
at the halted state.
Bits[N:3] are used for Frame List current
index. This means that each location of the
frame list is accessed 8 times before moving
to the next index.
USBCMD[Frame List Size] Number Elements N
00b
01b
10b
11b
(1024)
(512)
(256)
12
11
10
Reserved
Table 5-8 Frame index register
5.2.8 PERIODICLISTADDR register (address = 24h)
This 32-bit register contains the beginning address of the periodic frame list in the system memory.
Bit
Name
Type
Default value
Description
Periodic Frame List Base Address
[31:12]
PERI_BASEADR
R/W
20’h0
This 32-bit register contains the beginning
address of the
Periodic Frame List in the system memory.
These bits correspond to the memory address
signals[31:12].
[11:0]
Reserved
RO
12’b0
-
Table 5-9 Periodic frame list base address register
5.2.9 ASYNCLISTADDR register (address = 28h)
This 32-bit register contains the address of the next asynchronous queue head to be executed.
Bit
Name
Type
Default value
Description
Current Asynchronous List Address
[31:5]
ASYNC_LADR
R/W
27’h0
This 32-bit register contains the address of the
next asynchronous queue head to be
executed. These bits correspond to the
memory address signals [31:5].
[4:0]
Reserved
RO
5’b0
-
Table 5-10 Current asynchronous list address register
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