ST92F124 Datasheet, PDF (150/426 Pages) STMicroelectronics – 8/16-BIT SINGLE VOLTAGE FLASH MCU FAMILY WITH RAM, E3 TMEMULATED EEPROM, CAN 2.0B AND J1850 BLPD

ST92F124/F150/F250 - I/O PORTS
9 I/O PORTS
9.1 INTRODUCTION
ST9 devices feature flexible individually program-
mable multifunctional input/output lines. Refer to
the Pin Description Chapter for specific pin alloca-
tions. These lines, which are logically grouped as
8-bit ports, can be individually programmed to pro-
vide digital input/output and analog input, or to
connect input/output signals to the on-chip periph-
erals as alternate pin functions. All ports can be in-
dividually configured as an input, bi-directional,
output or alternate function. In addition, pull-ups
can be turned off for open-drain operation, and
weak pull-ups can be turned on in their place, to
avoid the need for off-chip resistive pull-ups. Ports
configured as open drain must never have voltage
on the port pin exceeding V_DD (refer to the Electri-
cal Characteristics section). Depending on the
specific port, input buffers are software selectable
to be TTL or CMOS compatible, however on Sch-
mitt trigger ports, no selection is possible.
Figure 79. I/O Register Map
9.2 SPECIFIC PORT CONFIGURATIONS
Refer to the Pin Description chapter for a list of the
specific port styles and reset values.
9.3 PORT CONTROL REGISTERS
Each port is associated with a Data register
(PxDR) and three Control registers (PxC0, PxC1,
PxC2). These define the port configuration and al-
low dynamic configuration changes during pro-
gram execution. Port Data and Control registers
are mapped into the Register File as shown in Fig-
ure 79. Port Data and Control registers are treated
just like any other general purpose register. There
are no special instructions for port manipulation:
any instruction that can address a register, can ad-
dress the ports. Data can be directly accessed in
the port register, without passing through other
memory or “accumulator” locations.
GROUP E
GROUP F
PAGE 2
FFh Reserved
FEh
P3C2
FDh
P3C1
FCh
P3C0
System
Registers
FBh Reserved
FAh
P2C2
F9h
P2C1
F8h
P2C0
F7h Reserved
F6h
P1C2
E5h
P5DR
R229 F5h
P1C1
E4h
P4DR
R228 F4h
P1C0
E3h
P3DR
R227 F3h Reserved
E2h
P2DR
R226 F2h
P0C2
E1h
P1DR
R225 F1h
P0C1
E0h
P0DR
R224 F0h
P0C0
GROUP F
PAGE 3
P7DR
P7C2
P7C1
P7C0
P6DR
P6C2
P6C1
P6C0
Reserved
P5C2
P5C1
P5C0
Reserved
P4C2
P4C1
P4C0
GROUP F
PAGE 43
P9DR
P9C2
P9C1
P9C0
P8DR
P8C2
P8C1
P8C0
Reserved
R255
R254
R253
R252
R251
R250
R249
R248
R247
R246
R245
R244
R243
R242
R241
R240
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