
DS89C430/DS89C440/DS89C450 Ultra-High-Speed Flash Microcontrollers 
44 of 48 
Stop Mode 
Stop mode disables all circuits within the processor. All on-chip clocks, timers, and serial port communication are 
stopped, and no processing is possible. 
Stop mode is invoked by setting the stop bit (PCON.1) to logic 1. The processor enters stop mode on the 
instruction that sets the bit. The processor can exit stop mode by using any of the six external interrupts that are 
enabled. 
An external reset through the RST pin unconditionally exits the processor from stop mode. If the BGS bit is set to 
logic 1, the bandgap provides a reset while in stop mode if V
CC
 should drop below the V
RST
 level. If BGS is 0, no 
reset is generated if V
CC
 drops below V
RST
. 
When the stop mode is removed, the processor waits for 65,536 clock cycles for the internal flash memory to warm 
up before starting normal execution. Also, the processor waits for the crystal warmup period if it is not using the 
ring oscillator. 
Serial I/O 
The microcontroller provides a serial port (UART) that is identical to the 80C52. In addition, it includes a second 
hardware serial port that is a full duplicate of the standard one. This port optionally uses pins P1.2 (RXD1) and 
P1.3 (TXD1) and has duplicate control functions included in new SFR locations. 
Both ports can operate simultaneously but can be at different baud rates or modes. The second serial port has 
similar control registers (SCON1 at C0h, SBUF1 at C1h) to the original. The new serial port can only use timer 1 for 
timer-generated baud rates. 
Control for serial port 0 is provided by the SCON0 register, while its I/O buffer is SBUF0. The registers SCON1 and 
SBUF1 provide the same functions for the second serial port. A full description of the use and operation of both 
serial ports can be found in the 
Ultra-High-Speed Flash Microcontroller User’s Guide. 
Instruction Set 
All instructions are 100% binary compatible with the industry-standard 8051, and are only different in the number of 
machine cycles used for the instructions. There are some special conditions and features to be considered when 
analyzing the DS89C430 instruction set. Full details are available in the 
Ultra-High-Speed Flash Microcontroller 
User’s Guide.
SELECTOR GUIDE 
MAX 
CLOCK 
SPEED 
(MHz) 
DS89C430
-MNL 
-40°C to +85°C 
16kB x 8 
33 
DS89C430-QNL 
-40°C to +85°C 
16kB x 8 
33
DS89C430-ENL 
-40°C to +85°C 
16kB x 8 
33
DS89C440
-MNL 
-40°C to +85°C 
32kB x 8 
33
DS89C440-QNL 
-40°C to +85°C 
32kB x 8 
33
DS89C440-ENL 
-40°C to +85°C 
32kB x 8 
33
DS89C450
-MNL 
-40°C to +85°C 
64kB x 8 
33
DS89C450-QNL 
-40°C to +85°C 
64kB x 8 
33
DS89C450-ENL 
-40°C to +85°C 
64kB x 8 
33
DS89C430
-MNG 
-40°C to +85°C 
16kB x 8 
25 
DS89C430-QNG 
-40°C to +85°C 
16kB x 8 
25
DS89C430-ENG 
-40°C to +85°C 
16kB x 8 
25
DS89C440
-MNG 
-40°C to +85°C 
32kB x 8 
25
DS89C440-QNG 
-40°C to +85°C 
32kB x 8 
25
DS89C440-ENG 
-40°C to +85°C 
32kB x 8 
25
DS89C450
-MNG 
-40°C to +85°C 
64kB x 8 
25
DS89C450-QNG 
-40°C to +85°C 
64kB x 8 
25
DS89C450-ENG 
-40°C to +85°C 
64kB x 8 
25
PART 
TEMP RANGE 
FLASH 
MEMORY 
SIZE 
PIN-PACKAGE 
40 PDIP 
44 PLCC 
44 TQFP 
40 PDIP 
44 PLCC 
44 TQFP 
40 PDIP 
44 PLCC 
44 TQFP 
40 PDIP 
44 PLCC 
44 TQFP 
40 PDIP 
44 PLCC 
44 TQFP 
40 PDIP 
44 PLCC 
44 TQFP