Management Interface; Endian - NEC UPD98413 User Manual

4.8 Management Interface

The management interface provides an interface with the microprocessor that controls µPD98413.
microprocessor can access the internal registers of the µPD98413 via the management interface.
The µPD98413 supports 32-bit multiplexed synchronous bus for connecting a microprocessor. These buses are
general-purpose bus interfaces that require fewer external circuitries connecting the microprocessor bus.
Signal
MCLK
AD31-0
CS_B
UWE_B
R/W_B
RDY_B
INT_B

4.8.1 Endian

The microprocessor bus is set to little endian as the default condition after reset. To connect a microprocessor with
a big endian interface, set the MIFM bit of the MDDGEN register to "1".
The µPD98413 controls access by using AD1 (address) and UWE_B as follows. To UWE_B, a negative logic high-
order word valid signal or a negative logic 4-byte valid signal can be connected.
(a) Little endian (MIFM="0")
Address
AD1
0
0
1
1
(b) Big endian (MIFM="1")
Address
AD1
0
0
1
1
148
CHAPTER 4 INTERFACES
I/O
I Microprocessor bus Clock
I/O Address / data bus
I I/O chip select signal
I Upper word enable signal
I Read / write select signal
O Ready signal
O Interrupt Signal
UWE_B
0
1
0
1
UWE_B
0
1
0
1
PRELIMINARY
Description
Data
AD [31:16]
Bit [31:16]
Invalid
Bit [31:16]
Bit [31:16]
Data
AD [31:16]
Bit [31:16]
Bit [31:16]
Invalid
Invalid
NEC confidential and Proprietary
The
AD [15:0]
Bit [15:0]
Bit [15:0]
Invalid
Invalid
AD [15:0]
Bit [15:0]
Invalid
Bit [15:0]
Bit [15:0]