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User’s Manual S14054EJ4V0UM
16
CHAPTER 2 PIN FUNCTIONS
(1) Register interface
(1/2)
Pin Name
Pin No.
I/O
Function
CS#
70
I
Chip select.
When this signal is low, the internal registers of the chip can be accessed.
RW
165
I
Host read/write.
This pin is used by the host system to access the register bus. When a high
level is input to this pin, the register bus is accessed for read. When a low
level is input, the register bus is accessed for write.
A[10:0]
251, 71, 166, 252,
72, 167, 253, 168,
73, 254, 255
I
Register address.
The address necessary for selecting a port or register to be accessed when
an internal register of the
µ
PD98431 is to be accessed is given to A[10:0].
The
µ
PD98431 has a 32-bit register for each port. A[10:8] specifies a port,
and A[7:0] specifies a register address.
The relation between the setting of A[10:8] and a port number is as follows:
Port 0
→
A[10:8] = 000B
Port 1
→
A[10:8] = 001B
Port 2
→
A[10:8] = 010B
Port 3
→
A[10:8] = 011B
Port 4
→
A[10:8] = 100B
Port 5
→
A[10:8] = 101B
Port 6
→
A[10:8] = 110B
Port 7
→
A[10:8] = 111B
D[31:0]
49, 50, 235, 51,
52, 148, 147, 53,
236, 149, 54, 237,
150, 55, 238, 151,
56, 239, 152, 57,
320, 240, 153, 58,
241, 154, 59, 242,
155, 60, 243, 244
I/O,
3-state
Register data
These pins form a bidirectional data bus through which the internal registers
of the
µ
PD98431 are accessed.
INT#
329
O,
open
drain
Interrupt signal.
Interrupt request signal. This signal goes low if an interrupt source is
generated. It is kept low until all the interrupt statuses are cleared if an
interrupt occurs.
This signal is an open-drain output signal.
RESET#
48
I
Hardware reset.
Active-low asynchronous reset signal. Immediately after hardware reset, all
the registers are set to their default values, and all the FIFOs and counters
are cleared.
ACK#
164
O
3-state
Register data acknowledge.
This signal indicates that the data on D[31:0] is valid when a register is read.
When this signal is low, the data read from the register exists on D[31:0].
When a register is written, this signal indicates completion of the writing.