DS89C430-DS89C450 Dallas Semiconducotr, DS89C430-DS89C450 Datasheet - Page 13

• Manufacturer Part Number: DS89C430-DS89C450
• Description: Ultra-High-Speed Flash Microcontrollers
• Manufacturer: Dallas Semiconducotr

PIN DESCRIPTION (continued)
PDIP
21
22
23
24
25
26
27
28
10
11
12
13
14
15
16
17
31
1
2
3
4
5
6
7
8
PLCC
24
25
26
27
28
29
30
31
11
13
14
15
16
17
18
19
35
2
3
4
5
6
7
8
9
PIN
TQFP
40
41
42
43
44
18
19
20
21
22
23
24
25
10
11
12
13
29
1
2
3
5
7
8
9
P2.2(A10)
P2.3(A11)
P2.4(A12)
P2.5(A13)
P2.6(A14)
P2.7(A15)
P2.0 (A8)
P2.1 (A9)
NAME
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
EA
Port 2 (A8–A15), I/O. Port 2 is an 8-bit, bidirectional I/O port. The reset condition of port 2
is logic high. In this state, a weak pullup holds the port high. This condition also serves as
an input mode, since any external circuit that writes to the port overcomes the weak
pullup. When software writes a 0 to any port pin, the DS89C430/DS89C440/DS89C450
activate a strong pulldown that remains on until either a 1 is written or a reset occurs.
Writing a 1 after the port has been at 0 causes a strong transition driver to turn on,
followed by a weaker sustaining pullup. Once the momentary strong driver turns off, the
port again becomes both the output high and input state. As an alternate function, port 2
can function as the MSB of the external address bus when reading external program
memory and read/write external RAM or peripherals. In page mode 1, port 2 provides both
the MSB and LSB of the external address bus. In page mode 2, it provides the MSB and
data.
Port 3, I/O. Port 3 functions as both an 8-bit, bidirectional I/O port and an alternate
functional interface for external interrupts, serial port 0, timer 0 and 1 inputs, and RD and
WR strobes. The reset condition of port 3 is with all bits at a logic 1. In this state, a weak
pullup holds the port high. This condition also serves as an input mode, since any external
circuit that writes to the port overcomes the weak pullup. When software writes a 0 to any
port pin, the DS89C430/DS89C440/DS89C450 activate a strong pulldown that remains on
until either a 1 is written or a reset occurs. Writing a 1 after the port has been at 0 causes
a strong transition driver to turn on, followed by a weaker sustaining pullup. Once the
momentary strong driver turns off, the port again becomes both the output high and input
state. The alternate modes of port 3 are as follows:
External Access. Allows selection of internal or external program memory. Connect to
ground to force the DS89C430/DS89C440/DS89C450 to use an external memory program
memory. The internal RAM is still accessible as determined by register settings. Connect
to V
Port 1, I/O. Port 1 functions as both an 8-bit, bidirectional I/O port and an alternate
functional interface for timer 2 I/O, new external interrupts, and new serial port 1. The
reset condition of port 1 is with all bits at logic 1. In this state, a weak pullup holds the port
high. This condition also serves as an input state, since any external circuit that writes to
the port overcomes the weak pullup. When software writes a 0 to any port pin, the
DS89C430/DS89C440/DS89C450 activate a strong pulldown that remains on until either
a 1 is written or a reset occurs. Writing a 1 after the port has been at 0 causes a strong
transition driver to turn on, followed by a weaker sustaining pullup. Once the momentary
strong driver turns off, the port again becomes the output high (and input) state. The
alternate functions of port 1 are as follows:
PORT
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
PORT
P3.7
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
CC
to use internal flash memory.
13 of 47
INT5
ALTERNATE
T2
T2EX
RXD1
TXD1
INT2
INT3
INT4
ALTERNATE
RXD0
TXD0
INT0
INT1
T0
T1
WR
RD
FUNCTION
External I/O for Timer/Counter2
Timer 2 Capture/Reload Trigger
Serial Port 1 Receive
Serial Port 1 Transmit
External Interrupt 2 (Positive Edge Detect)
External Interrupt 3 (Negative Edge Detect)
External Interrupt 4 (Positive Edge Detect)
External Interrupt 5 (Negative Edge Detect)
FUNCTION
Serial Port 0 Receive
Serial Port 0 Transmit
External Interrupt 0
External Interrupt 1
Timer 0 External Input
Timer 1 External Input
External Data Memory Write Strobe
External Data Memory Read Strobe
FUNCTION