Miscellaneous registers (Misc)
RM0082
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Doc ID 018672 Rev 1
12.4.41 USB_TUN_PRM
register
To enable adjusting various USB 2.0 specification-related characteristics, the USB 2.0
nanoPHY provides top level parameter override bits. The USB 2.0 nanoPHY is designed to
a default setting of these bits, and you are not expected to have to change these bits from
their default setting.
These override bits are not intended for per-part centering or dynamic centering. However,
there might be circumstances that require bit settings that are different than the default. If a
change is required, statically set these bits to the same value for all product parts. Statistical
analysis of the USB 2.0 nanoPHY's silicon characterization will determine whether any of
these bits require a different setting other than the default.
12.4.42 PLGPIOn_PAD_PRG
Registers
These five registers are used to program FAST IO pad's Drive strength, Pull up, pull down
status and Slew parameters. Depending upon the value of the above parameters following
tables govern their behaviour.
Table 193.
USB_TUN_PRM register bit assignments
USB0/1/2_TUN_PRM
0x120/4/8
Bit
Name
Reset
Value
Description
[31:18]
RFU
-
Reserved for future use (Write don’t care - Read
return zeros)
[17:15]
COMPDISTUNE[02:00]
3’h4
COMPDISTUNE
[14:12]
SQRXTUNE[2:0] 3'h3
SQRXTUNE
[11:08]
TXFSLSTUNE[3:0] 4'h3
TXFSLSTUNE
[07:04]
TXVREFTUNE[3:0]
4'h8
TXVREFTUNE
[03]
TXPREEMPHASISTUNE
1’h0
TXPREEMPHASISTUNE
[02:01]
TXHSXVTUNE[1:0]
2'h3
TXHSXVTUNE
[00]
TXRISETUNE
1’h0
TXRISETUNE
Table 194.
Drive selection
DRV[0]
DRV[1]
OUTPUT DRIVE
0
0
4mA
0
1
6mA
1
0
8mA
1
1
12mA