Cmsemicon CMS32L051 - Pull-Down Resistor Selection Register (Pdxx)

V1.2.2
CMS32L051 User Manual |Chapter 2 Pin Function
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2.3.6 Pull-down resistor selection register (PDxx)
Selection register for internal pull-down resistors. The internal pull-down resistor can only be used in bits
for bits specified by the drop-down resistor select register using the pin using the internal pull-down resistor and
the POMmn bit is 0 and set to input mode (PMmn=1). For bits set to output mode, independent of the setting
of the pull-down resistor selection register, no internal pull-down resistor is connected. The same is true when
used as the output pin for the multiplexing function or when set to an analog function.
After the reset signal is generated, the values of these registers become 00H.
Register address = base address + offset address; the base address of the PD register is 0x40040000, and
the offset address is shown in the figure below.
Figure 2-6 Format of pull-up resistor selection register
symbol
7
6
5
4
3
2
1
0
address
After reset
R/W
PD0
0
0
0
0
0
0
PD01
PD00
0x040
00H
R/W
PD1
PD17
PD16
PD15
PD14
PD13
PD12
PD11
PD10
0x041
00 H
R/W
PD2
PD27
PD26
PD25
PD24
PD23
PD22
PD21
PD20
0x042
00H
R/W
PD3
0
0
0
0
0
0
PD31
PD30
0x043
00H
R/W
PD5
0
0
0
0
0
0
PD51
PD50
0x045
00H
R/W
PD6
0
0
0
0
PD63
PD62
PD61
note2
PD60
note2
0x046
00H
R/W
PD7
0
0
PD75
PD74
PD73
PD72
PD71
PD70
0x047
00H
R/W
PD12
0
0
0
0
0
0
0
PD120
0x04C
00H
R/W
PD13
0
PD136
0
0
0
0
0
PD130
0x04D
00H
R/W
PD14
PD147
PD146
0
0
0
0
0
PD140
0x04E
00H
R/W
PDmn
Selection of internal pull-down resistors for the Pmn pin (m=0~3, 5~7, 12~14, n=0~7).
0
Internal pull-down resistors are not connected.
1
Connect an internal pull-down resistor.
Note 1 The initial value must be set for the unassigned bits.
Note 2 It is limited to CMS32L051xx-S series products. For products other than the CMS32L051xx-S series, ports
P60 and P61 do not have pull-up and pull-down functions of their own and must be used with external pull-up
resistors.