DS5002FP Secure Microprocessor Chip
11 of 25
PIN DESCRIPTION
PIN
NAME
FUNCTION
11, 9, 7, 5,
1, 79, 77,
75
15, 17, 19,
21, 25, 27,
29, 31
49, 50, 51,
56, 58, 60,
64, 66
P0.0–P0.7
General-Purpose I/O Port 0. This port is open-drain and cannot drive a logic 1. It requires
external pullups. Port 0 is also the multiplexed expanded address/data bus. When used in
this mode, it does not require pullups.
P1.0–P1.7
General-Purpose I/O Port 1
P2.0–P2.7
General-Purpose I/O Port 2. Also serves as the MSB of the expanded address bus.
36
P3.0 RXD
General-Purpose I/O Port Pin 3.0. Also serves as the receive signal for the on-board UART.
This pin should
not
be connected directly to a PC COM port.
General-Purpose I/O Port Pin 3.1. Also serves as the transmit signal for the on-board UART.
This pin should
not
be connected directly to a PC COM port.
General-Purpose I/O Port Pin 3.2. Also serves as the active-low external interrupt 0.
General-Purpose I/O Port Pin 3.3. Also serves as the active-low external interrupt 1.
General-Purpose I/O Port Pin 3.4. Also serves as the timer 0 input.
General-Purpose I/O Port Pin 3.5. Also serves as the timer 1 input.
General-Purpose I/O Port Pin. Also serves as the write strobe for Expanded bus operation.
General-Purpose I/O Port Pin. Also serves as the read strobe for Expanded bus operation.
Active-High Reset Input. A logic 1 applied to this pin activates a reset state. This pin is pulled
down internally so this pin can be left unconnected if not used. An RC power-on reset circuit
is not needed and is
not
recommended.
38
P3.1 TXD
39
40
41
44
45
46
P3.2
INT0
P3.3
INT1
P3.4 T0
P3.5 T1
P3.6
WR
P3.7
RD
34
RST
70
ALE
Address Latch Enable. Used to demultiplex the multiplexed expanded address/data bus on
port 0. This pin is normally connected to the clock input on a ’373 type transparent latch.
47, 48
XTAL2, XTAL1
XTAL1, XTAL 2. Used to connect an external crystal to the internal oscillator. XTAL1 is the
input to an inverting amplifier and XTAL2 is the output.
Logic Ground
V
CC
- +5V
V
CCO
- V
CC
Output. This is switched between V
CC
and V
LI
by internal circuits based on the
level of V
CC
. When power is above the lithium input, power is drawn from V
CC
. The lithium cell
remains isolated from a load. When V
CC
is below V
LI
, the V
CCO
switches to the V
LI
source.
V
CCO
should be connected to the V
CC
pin of an SRAM.
Lithium Voltage Input. Connect to a lithium cell greater than V
LIMIN
and no greater than V
LIMAX
as shown in the electrical specifications. Nominal value is +3V.
Byte-Wide Address Bus Bits 14–0. This bus is combined with the nonmultiplexed data bus
(BD7–0) to access NV SRAM. Decoding is performed using
CE1
through
CE4
. Therefore,
BA15 is not actually needed. Read/write access is controlled by R/
W
. BA14–0 connect
directly to an 8k, 32k, or 128k SRAM. If an 8k RAM is used, BA13 and BA14 are
unconnected. If a 128k SRAM is used, the micro converts
CE2
and
CE3
to serve as A16 and
A15, respectively.
Byte-Wide Data Bus Bits 7–0. This 8-bit bidirectional bus is combined with the
nonmultiplexed address bus (BA14–0) to access NV SRAM. Decoding is performed on
CE1
and
CE2
. Read/write access is controlled by R/
W.
D7–0 connect directly to an SRAM, and
optionally to a real-time clock or other peripheral.
Read/Write. This signal provides the write enable to the SRAMs on the byte-wide bus. It is
controlled by the memory map and partition. The blocks selected as program (ROM) are
write-protected.
Chip Enable 1. This is the primary decoded chip enable for memory access on the byte-wide
bus. It connects to the chip-enable input of one SRAM.
CE1
is lithium-backed. It remains in a
logic-high inactive state when V
CC
falls below V
LI
.
Chip Enable 2. This chip enable is provided to access a second 32k block of memory. It
connects to the chip-enable input of one SRAM. When MSEL = 0, the micro converts
CE2
into A16 for a 128k x 8 SRAM.
CE2
is lithium-backed and remains at a logic high when V
CC
falls below V
LI
.
Chip Enable 3. This chip enable is provided to access a third 32k block of memory. It
connects to the chip enable input of one SRAM. When MSEL = 0, the micro converts
CE3
52
13
GND
V
CC
12
V
CCO
54
VLI
16, 8, 18,
80, 76, 4, 6,
20, 24, 26,
28, 30, 33,
35, 37
BA14–0
71, 69, 67,
65,
61, 59, 57,
55
BD7–0
10
R/
W
74
CE1
2
CE2
63
CE3