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DS89C420
Ultra-High-Speed Microcontroller
www.maxim-ic.com
FEATURES
PIN ASSIGNMENT (Top View)
§ 80C52 compatible
P1.0/T2
P1.1/T2EX
P1.2/RXD1
P1.3/TXD1
P1.4/INT2
P1.5/INT3
P1.6/INT4
P1.7/INT5
RST
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
VCC
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
EA/VPP
ALE/PROG
PSEN
P2.7
- 8051 pin and instruction-set compatible
- Four bidirectional I/O ports
- Three 16-bit timer counters
- 256 bytes scratchpad RAM
§ On-chip memory
P3.0/RXD0
P3.1/TXD0
P3.2/INT0
P3.3/INT1
P3.4/T0
DS89C420
- 16kB flash memory
- In-system programmable through serial
port
P2.6
P2.5
P3.5/T1
- 1kB SRAM for MOVX
P3.6/WR
P3.7/RD
P2.4
P2.3
§ ROMSIZE feature
XTAL2
XTAL1
P2.2
P2.1
- Selects internal program memory size from
0 to 16k
VSS
P2.0
40-Pin DIP
- Allows access to entire external memory
map
6
1
40
- Dynamically adjustable by software
7
39
§ High-speed architecture
- 1 clock-per-machine cycle
- DC to 33MHz operation
DS89C420
- Single-cycle instruction in 30ns
- Optional variable length MOVX to access
fast/slow peripherals
- Dual data pointers with auto
increment/decrement and toggle select
- Supports four paged modes
17
29
18
33
28
23
44-Pin PLCC
§ Power Management Mode
- Programmable clock divider
- Automatic hardware and software exit
§ Two full-duplex serial ports
§ Programmable watchdog timer
§ 13 interrupt sources (six external)
§ Five levels of interrupt priority
§ Power-fail reset
34
44
22
12
DS89C420
§ Early warning power-fail interrupt
1
11
44-Pin TQFP
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple
revisions of any device may be simultaneously available through various sales channels. For information about device errata,
click here: http://www.maxim-ic.com/errata.
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