Portwell PEB-2131VG2A, Руководство пользователя

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System Installation
PEB-2131VG2A User’s Manual 3-7
Definitions of Variables:
Each bit in the lower nibble of each Register represents the setting of a GPIO port.
Bit0 vs. GPIO port 0
Bit1 vs. GPIO port 1
Bit2 vs. GPIO port 2
Bit3 vs. GPIO port 3
Bit4 vs. GPIO port 5
Bit5 vs. GPIO port 6
Bit6 vs. GPIO port 7
Bit7 vs. GPIO port 8
Value of
Inversion Register :
Only lower nibble is available for this function.
When set to a ‘1’, the incoming/outgoing port value is inverted.
When set to a ‘0’, the incoming/outgoing port value is the same as in Data Register.
Value of
I/O Selection Register :
Only lower nibble is available for this function.
When set to a ‘1’, respective GPIO port is programmed as an input port.
When set to a ‘0’, respective GPIO port is programmed as an output port.
Value of
Output Data / Input Data :
Only lower nibble is available for this function.
If a port is assigned to be an output port, then its respective bit can be read/written.
If a port is assigned to be an input port, then its respective bit can be read only.
Notes:
1) All the Buffered Digital Outputs are open-drain amplified form corresponding
GPIO ports.
2) Some other functions may occupy the high nibble of the registers. Altering any
content in high nibble will be undesired.