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Document # 001-20559 Rev. *D
General Purpose IO (GPIO)
6.2.4
PRTxDMx Registers
The Port Drive Mode Bit Registers (PRTxDMx) are used to
specify the Drive mode for GPIO pins.
Bits 7 to 0: Drive Mode x[7:0].
In the PRTxDMx registers
there are eight possible drive modes for each port pin. Three
mode bits are required to select one of these modes, and
these three bits are spread into three different registers
(PRTxDM0, PRTxDM1, and PRTxDM2). The bit position of
the effected port pin (for example, Pin[2] in Port 0) is the
same as the bit position of each of the three drive mode reg-
ister bits that control the Drive mode for that pin (for exam-
ple, bit[2] in PRT0DM0, bit[2] in PRT0DM1, and bit[2] in
PRT0DM2). The three bits from the three registers are
treated as a group. These are referred to as DM2, DM1, and
DM0, or together as DM[2:0]. Drive modes are shown in
For analog IO, the Drive mode should be set to one of the
High Z modes, either 010b or 110b. The 110b mode has the
advantage that the block’s digital input buffer is disabled, so
no
current flows even when the analog input is not
close to either power rail. When digital inputs are needed on
the same pin as analog inputs, the 010b Drive mode should
be used. If the 110b Drive mode is used, the pin is always
read as a zero by the CPU and the pin is not able to gener-
ate a useful interrupt. (It is not strictly required that a High Z
mode be selected for analog operation.)
For global input modes, Drive mode must be set to 010b.
The GPIO provides a default Drive mode of high imped-
ance, analog (High Z). This is achieved by forcing the reset
state of all PRTxDM1 and PRTxDM2 registers to FFh.
The resistive drive modes place a
the output, for low outputs (mode 000b) or high outputs
(mode 011b). Strong Drive mode 001b gives the fastest
edges at high DC drive strength. Mode 101b gives the same
drive strength but with slower edges. The open-drain modes
(100b and 111b) also use the slower edge rate drive. These
modes enable open-drain functions such as I2C mode 111b
(although the slow edge rate is not slow enough to meet the
I2C fast mode specification).
For additional information, refer to the
, the
, and the
.
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Access
0,xxh
Drive Mode 2[7:0]
RW : FF
1,xxh
Drive Mode 0[7:0]
RW : 00
1,xxh
Drive Mode 1[7:0]
RW :
FF
LEGEND
xx An “x” after the comma in the address field indicates that there are multiple instances of the register. For an expanded address listing of these registers,
refer to the
“Summary Table of the Core Registers” on page 32
.
Table 6-1. Pin Drive Modes
Drive Modes
Pin State
Description
DM2
DM1
DM0
0
0
0
Resistive pull down
Strong high, resistive low
0
0
1
Strong drive
Strong high, strong low
0
1
0
High impedance
High Z high and low, digital
input enabled
0
1
1
Resistive pull up
Resistive high, strong low
1
0
0
Open drain high
Slow strong high, High Z low
1
0
1
Slow strong drive
Slow strong high, slow strong
low
1
1
0
High impedance,
analog (
reset state
)
High Z high and low, digital
input disabled (for zero
power) (
reset state
)
1
1
1
Open drain low
Slow strong low, High Z high
Summary of Contents for PSoC CY8C23533
Page 4: ...Contents Overview 4 Document 001 20559 Rev D Section G Glossary 385 Index 401 ...
Page 16: ...Contents Overview 16 Document 001 20559 Rev D ...
Page 24: ...24 Document 001 20559 Rev D Section A Overview ...
Page 30: ...30 Document 001 20559 Rev D Pin Information ...
Page 54: ...54 Document 001 20559 Rev D Supervisory ROM SROM ...
Page 60: ...60 Document 001 20559 Rev D RAM Paging ...
Page 68: ...68 Document 001 20559 Rev D Interrupt Controller ...
Page 76: ...12 Document 001 20559 Rev D General Purpose IO GPIO ...
Page 82: ...18 Document 001 20559 Rev D Internal Main Oscillator IMO ...
Page 84: ...20 Document 001 20559 Rev D Internal Low Speed Oscillator ILO ...
Page 90: ...26 Document 001 20559 Rev D External Crystal Oscillator ECO ...
Page 94: ...30 Document 001 20559 Rev D Phase Locked Loop PLL ...
Page 106: ...42 Document 001 20559 Rev D Sleep and Watchdog ...
Page 228: ...164 Document 001 20559 Rev D Section D Digital System ...
Page 234: ...170 Document 001 20559 Rev D Array Digital Interconnect ADI ...
Page 278: ...214 Document 001 20559 Rev D Digital Blocks ...
Page 296: ...232 Document 001 20559 Rev D Analog Interface ...
Page 304: ...240 Document 001 20559 Rev D Analog Array ...
Page 308: ...244 Document 001 20559 Rev D Analog Input Configuration ...
Page 312: ...248 Document 001 20559 Rev D Analog Reference ...
Page 338: ...274 Document 001 20559 Rev D Section F System Resources ...
Page 354: ...290 Document 001 20559 Rev D Multiply Accumulate MAC ...
Page 374: ...310 Document 001 20559 Rev D I2C ...
Page 400: ...336 Document 001 20559 Rev D Section G Glossary ...