HD6432646 Hitachi, HD6432646 Datasheet - Page 55

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Type
Clock
Operating mode
control
System control
Interrupts
Address bus
Data bus
Bus control
Symbol
OSC2
ø
MD2 to MD0
RES
STBY
FWE
NMI
IRQ5 to IRQ0 Input
A23 to A0
D15 to D0
AS
RD
I/O
Input
Output
Input
Input
Input
Input
Input
Output
I/O
Output
Output
Name and Function
Subclock: Connects to a 32 kHz crystal oscillator.
See section 21, Clock Pulse Generator, for typical
connection diagrams for a crystal oscillator.
System clock: Supplies the system clock to an external
device.
Mode pins: These pins set the operating mode.
The relation between the settings of pins MD2 to MD0
and the operating mode is shown below. These pins
should not be changed while the H8S/2646 Series is
operating.
MD2
0
1
Reset input: When this pin is driven low, the chip is
reset.
Standby: When this pin is driven low, a transition is
made to hardware standby mode.
Flash write enable: Pin for flash memory use (in
planning stage).
Nonmaskable interrupt: Requests a nonmaskable
interrupt. When this pin is not used, it should be fixed
high.
Interrupt request 5 to 0: These pins request a
maskable interrupt.
Address bus: These pins output an address.
Data bus: These pins constitute a bidirectional data
bus.
Address strobe: When this pin is low, it indicates that
address output on the address bus is enabled.
Read: When this pin is low, it indicates that the
external address space can be read.
MD1
0
1
0
1
MD0
0
1
0
1
0
1
0
1
Operating Mode
—
—
—
—
Mode 4
Mode 5
Mode 6
Mode 7
21