PCMCIA Interface
17-6
MPC823 USER’S MANUAL
MOTOROLA
PCMCIA
INTERFACE
17
Speaker (SPKR)—Input. When the card and its socket are programmed for I/O
interface operation, the BVD2_B signal is used as SPKR and it is generated by the I/O
PC cards. The SPKR signal must be used to provide the socket’s single amplitude
(digital) audio waveform to the system. The SPKR signal is routed out the SPKROUT
signal if the card and its socket are programmed for I/O interface operation.
Ready/Busy/Interrupt Request (RDY/BSY_B/IREQ_B)—Input. When the card and its
socket are programmed for memory interface operation, this signal is used as RDY/
BSY_B and must be asserted low by a PC card to indicate that the PC card is busy
processing a previous WRITE command. When the card and its socket are
programmed for I/O operation, this signal is used as IREQ_B and must be asserted low
to generate an interrupt. This signal must be set high when no interrupt is requested.
This signal is connected to the IP_B[7] pin.
17.3.3 The PCMCIA Output Port Signals
The following signals are used by a PCMCIA slot to control the RESET signal to the card
and the output enable of the buffers to the card. The MPC823 provides a way for the
software to control the output signal state. This function is not necessarily specific to the
PCMCIA interface and these signals may be used by a system as a general-purpose output
port. These signals appear on the OP[2:3] pins. The OP[2:3] pins, when not operating the
PCMCIA controller, can be accessed as general-purpose outputs through the CBOE and
CBRESET bits of the PGCRB register.
Card Reset (RESET_B)—Output. This signal is provided to clear the card configuration
option register residing on the card, thus placing the card in its default (memory-only
interface) state and initiating the beginning of any additional card initialization.
RESET_B is connected to the OP3 pin.
PCMCIA Buffers Output Enable (POE_B)—Output. This line is an output port line
reflecting the value of the CBOE bit in the PCMCIA interface power control register. It
should be used to three-state the address and strobe pins addressing the slot. POE_B
is connected to the OP2 pin.
17.3.4 Other PCMCIA Signals
The following special function signals can be used by the PCMCIA socket. Their function is
not necessarily specific to PCMCIA and these signals can be used by a system for other
functions.
Power Is On (IRQ)—Input. One IRQ signal provided for general-purpose interrupt
requests may be used by the card power supply circuitry to notify the MPC823
processor when the power supply to the card has reached the required voltage.
Speaker out (SPKROUT)—Output. This signal is used to provide a digital audio
waveform that is to be driven to the system’s speaker. It is generated from the SPKR
input port signal.