ISD91200 Series Technical Reference Manual
Release Date: Sep 16, 2019
- 410 -
Revision 2.4
VMID Control Register (ANA_VMID)
Register
Offset
R/W
Description
Reset Value
ANA_VMID
0x00
R/W
VMID Reference Control Register
0x0000_0007
7
6
5
4
3
2
1
0
Reserved
PDHIRES
PDLORES
PULLDOWN
Table 7-6 VMID Control Register (ANA_VMID, address 0x4008_0000).
Bits
Description
[31:3]
Reserved
Reserved.
[2]
PDHIRES
Power Down High (360k
Ω
) Resistance Reference
0= Connect the High Resistance reference to VMID. Use this setting for minimum power consumption.
1= The High Resistance reference is disconnected from VMID. Default power down and reset
condition.
[1]
PDLORES
Power Down Low (4.8k
Ω
) Resistance Reference
0= Connect the Low Resistance reference to VMID. Use this setting for fast power up of VMID. Can be
turned off after 50ms to save power.
1= The Low Resistance reference is disconnected from VMID. Default power down and reset
condition.
[0]
PULLDOWN
VMID Pulldown
0= Release VMID pin for reference operation.
1= Pull VMID pin to ground. Default power down and reset condition.
7.4.5
LDO Power Domain Control
The ISD91200 provides a Low Dropout Regulator (LDO)
that provides power to the I/O domain of GPIOA[7:0]. Using
this regulator device can operate from a 5V supply rail and
generate a 1.5-3.3V regulated supply to operate the
GPIOA[7:0] domain and external loads up to 30mA. The
supply pin for the LDO is the VDDBS pin which should be
connected to VCCD. If the LDO is not used, both VDDBS
and VD33 should be tied to VCCD. Upon POR or reset the
default condition of the LDO is off, meaning supply will be
high impedance. Software must configure the LDO before
GPIOA[7:0] is usable (unless VD33=VCCD).
GPIOA[7]
GPIOA[0]
VCCLDO
LDOPD[1:0]
LDOSET[1:0]
VD33
LDO
VSSD
1
µ
F
0.1
µ
F
To load
Figure 7-7 LDO Power Domain