User Manual
BCM1250/BCM1125/BCM1125H
10/21/02
B r o a d c o m C o r p o r a t i o n
Document
1250_1125-UM100CB-R
Section 13: GPIO Page
397
GPIO lines can be enabled as interrupts in pairs. For each pair, both can have their interrupts disabled, both
can be level interrupts, both can be edge sensitive interrupts or one can be level and the other an edge
interrupt. This is selected in the
gpio_int_type
register. When a level interrupt is selected the input after
inversion and glitch filtering is directly passed to the interrupt mapper in the SCD (see
) where it must be high to signal an interrupt. If the edge detector is enabled, the
signal to the SCD is asserted when a rising edge is detected on the output of the glitch filter, the signal is
cleared when the corresponding bit is set in a write to the
gpio_clr_edge
register. A negative edge can be
detected by inverting the input. Masking of the GPIO interrupt lines is also done in the interrupt mapper. The
interrupt function is not affected by the direction of the line, if the GPIO pin is set as an output then the interrupt
will be raised whenever the output is set appropriately (after the glitch filtering delay).
Some of the GPIO pins are used by the PCMCIA controller and some to provide parity on the generic bus.
These functions are set by reset time configuration resistors on the generic bus AD lines. When used for
PCMCIA operation the input inverters must be disabled by leaving
gpio_input_invert
bits [15:6] in their default
state as zeros. The GPIO signals are summarized in the table below.
Table 275: GPIO Pins and Alternate Uses
GPIO Bit
Alternate Name
Alternate Use
1:0
S1:0_RSTROBE
Synchronous serial output strobes.
5:2
IO_ADP[3:0]
Generic bus parity.
6
PC_CE1_L
PCMCIA Card enable output.
7
PC_CE2_L
PCMCIA Card enable output.
8
PC_RESET
PCMCIA card reset output.
9
PC_READY
PCMCIA ready input.
10
PC_REG_L
PCMCIA regular/attribute select output.
11
PC_WP
PCMCIA write protected input.
12
PC_CD1_L
PCMCIA card detect input (the 1ms glitch filter is always used).
13
PC_CD2_L
PCMCIA card detect input (the 1ms glitch filter is always used).
14
PC_VS1_L
PCMCIA voltage sense input (the 60 ns glitch filter is always used).
15
PC_VS2_L
PCMCIA voltage sense input (the 60 ns glitch filter is always used).