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© Sealevel Systems, Inc.
4030 Manual | SL9362 9/2021
Programming the PIO-48, Continued
Presetting an Output Port
Each port has an output register associated with it. This register may be written and retains its value
whether the port is configured as an input or an output. To preset the value of an output port the program
should write to the port when it is configured as an input then configure it as an output.
Writing the Outputs
The outputs are active true. Writing a one (1) corresponds to 5V while writing a zero (0) corresponds to 0V,
at the output.
Register Description
Address
Mode
D7
D6
D5
D4
D3
D2
D1
D0
Base+0
Port A1
RD/WR
PA1D7 PA1D6 PA1D5 PA1D4 PA1D3 PA1D2
PA1D1 PA1D0
Base+1
Port B1
RD/WR
PB1D7
PB1D6 PB1D5 PB1D4 PB1D3 PB1D2
PB1D1
PB1D0
Base+2
Port C1
RD/WR
PC1D7 PC1D6 PC1D5 PC1D4 PC1D3 PC1D2
PC1D1 PC1D0
Base+3
CW Port 1
WR
CW1D7
0
0
CW1D4 CW1D3 CW1D2 CW1D1 CW1D0
Base+4
Port A2
RD/WR
PA2D7 PA2D6 PA2D5 PA2D4 PA2D3 PA2D2
PA2D1 PA2D0
Base+5
Port B2
RD/WR
PB2D7
PB2D6 PB2D5 PB2D4 PB2D3 PB2D2
PB2D1
PB2D0
Base+6
Port C2
RD/WR
PC2D7 PC2D6 PC2D5 PC2D4 PC2D3 PC2D2
PC2D1 PC2D0
Base+7
CW Port 2
WR
CW2D7
0
0
CW2D4 CW2D3 CW2D2 CW2D1 CW2D0
