DS80C310_1 Datasheet, PDF (4/21 Pages) Dallas Semiconductor – High-Speed Micro

DS80C310
DIP
1
2
3
4
5
6
7
8
21
22
23
24
25
26
27
28
10–17
10
11
12
13
14
15
16
17
31
–
PLCC
2
3
4
5
6
7
8
9
24
25
26
27
28
29
30
31
11,
13–19
11
13
14
15
16
17
18
19
35
12
34
TQFP
40
41
42
43
44
1
2
3
18
19
20
21
22
23
24
25
5, 7–13
5
7
8
9
10
11
12
13
29
6
28
SIGNAL
NAME
A8 (P2.0)
A9 (P2.1)
A10 (P2.2)
A11 (P2.3)
A12 (P2.4)
A13 (P2.5)
A14 (P2.6)
A15 (P2.7)
P3.0–P3.7
EA
NC
DESCRIPTION
Port
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
Alternate Function
T2
T2EX
none
none
INT2
INT3
INT4
INT5
External I/O for Timer/Counter 2
Timer/Counter 2 Capture/Reload Trigger
(DS80C320 has a serial port RXD)
(DS80C320 has a serial port TXD)
External Interrupt 2 (Positive Edge Detect)
External Interrupt 3 (Negative Edge Detect)
External Interrupt 4 (Positive Edge Detect)
External Interrupt 5 (Negative Edge Detect)
A8–15 (Port 2) – Output. Port 2 serves as the MSB for external
addressing. P2.7 is A15 and P2.0 is A8. The DS80C310 will auto-
matically place the MSB of an address on P2 for external ROM and
RAM access. Although Port 2 can be accessed like an ordinary
I/O port, the value stored on the Port 2 latch will never be seen on
the pins (due to memory access). Therefore writing to Port 2, in
software is only useful for the instructions MOVX A, @ Ri or MOVX
@ Ri, A. These instructions use the Port 2 internal latch to supply
the external address MSB. In this case, the Port 2 latch value will
be supplied as the address information.
Port 3 – I/O. Port 3 functions as both an 8–bit bi–directional I/O
port and an alternate functional interface for external Interrupts,
Serial Port 0, Timer 0 and 1 Inputs, RD and WR strobes. The reset
condition of Port 3 is with all bits at a logic 1. In this state, a weak
pull–up holds the port high. This condition also serves as an input
mode, since any external circuit that writes to the port will over-
come the weak pull–up. When software writes a 0 to any port pin,
the DS80C310 will activate a strong pull–down that remains on
until either a 1 is written or a reset occurs. Writing a 1 after the port
has been at 0 will cause a strong transition driver to turn on, fol-
lowed by a weaker sustaining pull–up. Once the momentary
strong driver turns off, the port once again becomes both the out-
put high and input state. The alternate modes of Port 3 are outlined
below.
Port
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
Alternate Mode
RXD0
TXD0
INT0
INT1
T0
T1
WR
RD
Serial Port 0 Input
Serial Port 0 Output
External Interrupt 0
External Interrupt 1
Timer 0 External Input
Timer 1 External Input
External Data Memory Write Strobe
External Data Memory Read Strobe
EA – Input. This pin must be connected to ground for proper
operation.
NC – Reserved. These pins should not be connected. They are
reserved for use with future devices in this family.
031296 4/21