DS80C390 Dual CAN High-Speed Microprocessor
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PIN DESCRIPTION (continued)
PIN
LQFP PLCC
NAME FUNCTION
58–64, 1
2–8, 10
P1.0–P1.7
Port 1, I/O.
Port 1 can function as an 8-bit bidirectional I/O port, the
nonmultiplexed A0–A7 signals (when the
MUX
pin = 1), and as an
alternate interface for internal resources. Setting the SP1EC bit
relocates RXD1 and TXD1 to Port 5. The reset condition of Port 1 is
all bits at logic 1 through a weak pullup. The logic 1 state also serves
as an input mode, since external circuits writing to the port can
overdrive the weak pullup. When software clears any port pin to 0, a
strong pulldown is activated that remains on until either a 1 is written
to the port pin or a reset occurs. Writing a 1 after the port has been at
0 activates a strong transition driver, followed by a weaker sustaining
pullup. Once the momentary strong driver turns off, the port once
again becomes the output (and input) high state.
Port Alternate
Function
58
2
A0
P1.0
T2 External I/O for Timer/Counter 2
59
3
A1
P1.1
T2EX Timer/Counter 2 Capture/Reload Trigger
60
4
A2
P1.2
RXD1 Serial Port 1 Input
61
5
A3
P1.3
TXD1 Serial Port 1 Output
62
6
A4
P1.4
INT2 External Interrupt 2 (Positive Edge Detect)
63 7 A5
P1.5
INT3
External Interrupt 3 (Negative Edge Detect)
64
8
A6
P1.6
INT4 External Interrupt 4 (Positive Edge Detect)
1 10 A7
P1.7
INT5
External Interrupt 5 (Negative Edge Detect)
35 46
A8
(P2.0)
36 47
A9
(P2.1)
37 48
A10
(P2.2)
38 49
A11
(P2.3)
39 50
A12
(P2.4)
42 53
A13
(P2.5)
43 54
A14
(P2.6)
44 55
A15
(P2.7)
A15–A8 (Port 2), Output.
Port 2 serves as the MSB for external
addressing. The port automatically asserts the address MSB during
external ROM and RAM access. Although the Port 2 SFR exists, the
SFR value never appears on the pins (due to memory access).
Therefore, accessing the Port 2 SFR is only useful for MOVX A, @Ri
or MOVX @Ri, A instructions, which use the Port 2 SFR as the
external address MSB.
4–7,
10–13
13–16,
19–22
P3.0–P3.7
Port 3, I/O.
Port 3 functions as an 8-bit bidirectional I/O port and as an
alternate interface for several resources found on the traditional 8051.
The reset condition of Port 1 is all bits at logic 1 through a weak pullup.
The logic 1 state also serves as an input mode, since external circuits
writing to the port can overdrive the weak pullup. When software clears
any port pin to 0, the device activates a strong pulldown that remains on
until either a 1 is written to the port pin or a reset occurs. Writing a 1 after
the port has been at 0 activates a strong transition driver, followed by a
weaker sustaining pullup. Once the momentary strong driver turns off,
the port once again becomes the output (and input) high state.
Port Alternate
Function
4
13
P3.0
RXD0 Serial Port 0 Input
5
14
P3.1
TXD0 Serial Port 0 Output
6 15
P3.2
INT0
External Interrupt 0
7 16
P3.3
INT1
External Interrupt 1
10
19
P3.4
T0 Timer 0 External Input
11
20
P3.5
T1/XCLK Timer 1 External Input/External Clock Output
12 21
P3.6
WR
External Data Memory Write Strobe
13 22
P3.7
RD
External Data Memory Read Strobe