SYSCFG Registers
275
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
System Configuration (SYSCFG) Module
10.5.19 VTP I/O Control Register (VTPIO_CTL)
The VTP I/O control register (VTPIO_CTL) is used to control the calibration of the DDR2/mDDR memory
controller I/Os with respect to voltage, temperature, and process (VTP). The voltage, temperature, and
process information is used to control the IO's output impedance. The VTPIO_CTL is shown in
and described in
Figure 10-46. VTP I/O Control Register (VTPIO_CTL)
31
24
Reserved
R-0
23
19
18
17
16
Reserved
VREFEN
VREFTAP
R-0
R/W-0
R/W-0
15
14
13
12
9
8
READY
IOPWRDN
CLKRZ
Reserved
PWRSAVE
R-0
R/W-0
R/W-0
R/W-0
R/W-0
7
6
5
3
2
0
LOCK
POWERDN
D
F
R/W-0
R/W-1
R/W-6h
R/W-7h
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 10-50. VTP I/O Control Register (VTPIO_CTL) Field Descriptions
Bit
Field
Value
Description
31-19
Reserved
0
Reserved
18
VREFEN
Internal DDR I/O Vref enable.
0
Connected to pad, external reference.
1
Reserved
17-16
VREFTAP
Selection for internal reference voltage level.
0
Vref = 50.0% of VDDS
1h-3h
Reserved
15
READY
VTP Ready status.
0
VTP is not ready.
1
VTP is ready.
14
IOPWRDN
Power down enable for DDR input buffer.
0
Disable power down control by the PWRDNEN bit in the DDR PHY control register 1 (DRPYC1R).
1
Enable power down control by the PWRDNEN bit in the DDR PHY control register 1 (DRPYC1R).
13
CLKRZ
0
VTP clear.
Write 0 to clear VTP flops.
12-9
Reserved
0
Reserved. Write the default value to all bits when modifying this register.
8
PWRSAVE
VTP power save mode.
Turn off power to the external resistor when it is not needed. The
PWRSAVE bit setting is only valid when the POWERDN bit is cleared to 0.
0
Disable power save mode.
1
Enable power save mode.
7
LOCK
VTP impedance lock.
Lock impedance value so that the VTP controller can be powered down.
0
Unlock impedance.
1
Lock impedance.
6
POWERDN
VTP power down.
Power down the VTP controller. The PWRSAVE bit setting is only valid when
the POWERDN bit is cleared to 0.
0
Disable power down.
1
Enable power down.