XR17L152 Datasheet, PDF (16/55 Pages) Exar Corporation – 3.3V PCI BUS DUAL UART

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XR17L152
3.3V PCI BUS DUAL UART
REV. 1.1.0
1.2.9 Multi-Purpose Inputs and Outputs
The L152 provides 8 multi-purpose inputs/outputs [MPIO7:0] for general use. Each pin can be programmed to
be an input or output function. The input logic state can be set for normal or inverted level, and optionally set to
generate an interrupt. The outputs can be set to be normal logic 1 or 0 state, or three-state. Their functions and
definitions are programmed through 5 registers: MPIOINT, MPIOLVL, MPIO3T, MPIOINV and MPIOSEL. If all 8
pins are set for inputs, all 8 interrupts would be or’ed together. The Or’ed interrupt is reported in the channel 0
UART interrupt status, see Interrupt Status Register. The pins may also be programmed to be outputs and to
the three-state condition for signal sharing.
1.2.10 MPIO REGISTER
Bit 7 represents MPIO7 pin and bit 0 represents MPIO0 pin. There are 5 registers that select, control and
monitor the 8 multipurpose inputs and output pins. Figure 6 shows the internal circuitry.
FIGURE 6. MULTIPURPOSE INPUT/OUTPUT INTERNAL CIRCUIT
MPIOINT [7:0]
INT
AND
Rising Edge
Detection
AND
MPIOLVL [7:0]
Read Input Level
MPIOINV [7:0]
(Input Inversion Enable =1)
MPIOLVL [7:0]
(Output Level)
MPIO3T [7:0]
(3-state Enable =1)
MPIOSEL [7:0]
(Select Input=1, Output=0 )
1
0
OR
MPIO
Pin [7:0]
MPIOCKT
16