XR17D154 Exar Corporation, XR17D154 Datasheet - Page 19

• Manufacturer Part Number: XR17D154
• Description: Four-channel Pci-bus Uart
• Manufacturer: Exar Corporation

XR17D154
UNIVERSAL (3.3V AND 5V) PCI BUS QUAD UART
REV. P1.0.0
The D154 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 tri-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 tri-state condition for signal sharing.
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 outputs pins.
2.2.9
2.2.10
Multi-Purpose Inputs and Outputs
MPIO REGISTER
F
IGURE
M PIO IN T [7:0]
M PIO LVL [7:0]
R ea d Inp ut Le vel
M PIO IN V [7:0]
(Inp ut In versio n E na ble =1 )
M PIO LVL [7:0]
(O utp ut Level)
M PIO 3T [7:0]
(3-sta te En ab le =1 )
M PIO SE L [7:0]
(S elect Inp ut=1 , O u tp ut= 0 )
IN T
8. M
ULTIPURPOSE INPUT
A N D
R ising Edge
D etection
O R
Figure 8
/
OUTPUT INTERNAL CIRCUIT
1
0
19
shows the internal circuitry.
A N D
Pin [7:0]
M PIO
M P IO C KT
PRELIMINARY
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