st20-gp1 STMicroelectronics, st20-gp1 Datasheet - Page 86

• Manufacturer Part Number: st20-gp1
• Description: Gps Processor
• Manufacturer: STMicroelectronics

ST20-GP1
PIn register
The data read from this register will give the logic level present on an input pin at the start of the
read cycle to this register. The read data will be the last value written to the register irrespective of
the pin configuration selected.
14.1.2 PIO bit configuration register
The PC1 register is used to configure each of the PIO port bits as an input or output. Writing a 0
configures the bit as an input, a 1 configures the bit as an output.
14.1.3 PIO Input compare and Compare mask registers
The input compare (PComp) register holds the value to which the input data from the PIO port pins
will be compared. If any of the input bits are different from the corresponding bits in the PComp
register, and the corresponding bit in the compare mask (PMask) register is set to 1, then the
internal interrupt signal for the port will be set to 1.
The compare function is sensitive to changes in levels on the pins and so the change in state on
the input pin must be greater in duration than the interrupt response time for the compare to be
seen as a valid interrupt by an interrupt service routine.
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PIn
Bit
0
1
2
3
4
5
PC1
Bit
0
1
2
3
4
5
Bit field
PIn0
PIn1
PIn2
PIn3
PIn4
PIn5
Bit field
ConfigData0
ConfigData1
ConfigData2
ConfigData3
ConfigData4
ConfigData5
PIO port base address + #10
PIO port base address + #30
Function
Input data bit 0
Input data bit 1
Input data bit 2
Input data bit 3
Input data bit 4
Input data bit 5
Function
Configures the PIO bit 0 as an input or an output.
Configures the PIO bit 1 as an input or an output.
Configures the PIO bit 2 as an input or an output.
Configures the PIO bit 3 as an input or an output.
Configures the PIO bit 4 as an input or an output.
Configures the PIO bit 5 as an input or an output.
Table 14.3 PC1 register format
Table 14.2 PIn register format
Read/Write
Read only