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CHAPTER 6 PIN FUNCTIONS
125
Table 6-1. System Bus Interface Signals (2/2)
Signal name
I/O
Definition
Function
SHB*
O
System Bus High Byte
Enable
PCMCIA bus high-order byte enable signal. This signal becomes active when
the high-order byte of the DATA bus is valid for access to PCMCIA.
IOR*
O
I/O Read
PCMCIA card I/O read signal. This signal becomes active when the V
R
4101
accesses the PCMCIA I/O port to read data.
IOW*
O
I/O Write
PCMCIA card I/O write signal. This signal becomes active when the V
R
4101
writes data to the PCMCIA I/O port.
MEMR*
O
Memory Read
PCMCIA card memory read signal. This signal becomes active when the
V
R
4101 accesses PCMCIA memory to read data.
MEMW*
O
Memory Write
PCMCIA card memory write signal. This signal becomes active when the
V
R
4101 accesses PCMCIA memory to write data.
ZWS*
I
Zero Wait State
PCMCIA zero wait state signal. Activate this signal when the PCMCIA
controller is ready to accept accesses from the V
R
4101.
IRQ
I
Interrupt Request
PCMCIA card IRQ signal. By asserting this pin, the PCMCIA controller sends
an interrupt request to the V
R
4101.
RSTOUT
O
PCM Reset
PCMCIA card reset signal. This signal becomes active when the V
R
4101 resets
the PCMCIA controller.
6.1.2 Clock Interface Signals
The clock interface signals are used to supply a 32-kHz clock. Table 6-2 lists the functions of these
signals.
Table 6-2. Clock Interface Signals
Signal name
I/O
Definition
Function
CLKX1
I
Clock X1
32-kHz clock input pin. This pin is used to connect a 32-kHz crystal.
CLKX2
I
Clock X2
32-kHz clock input pin. This pin is used to connect a second 32-kHz crystal.
V
DD
P
-
V
DD
for PLL
Quiet V
DD
for internal PLL circuit.
GNDP
-
GND for PLL
Quiet GND for internal PLL circuit.