SyncMOS Technologies International, Inc.
P3.0 – P3.7
10,11,12,13
14,15,16,17
5,7,8,9,
10,11,12,13
11, 13,14,15,
16,17,18,19
SM89S16R1
Port 3:
Port 3 is an 8-bits bidirectional I/O port with internal
pull-ups. Port 3 pins that have 1s written to them are pulled
high by the internal pull-ups and can be used as inputs. As
inputs, port 3 pins that are externally being pulled low will
source current because of the pull-ups. (See DC Electrical
Characteristics: IIL). Port 3 also serves the special features.
Port Pin
Alternative function
P3.0
RxD UART input
P3.1
TxD UART output
P3.2
#EX0 external interrupt 0
P3.3
#EX1 external interrupt 1
P3.4
T0: Timer 0 external input
P3.5
T1: Timer 1 external input
P3.6
#WR External data memory write strobe
P3.7
#RD External data memory read strobe
Address Latch Enable:
Output pulse for latching the low byte of the address during
an access to external memory. In normal operation, ALE is
emitted twice every machine cycle, and can be used for
external timing or clocking. Note that one ALE pulse is
skipped during each access to external data memory. Setting
SFR SCONF.0 can disable ALE. With this bits set, ALE will
be active only during a MOVX instruction.
X32OUT: The 32.768KHz crystal output for RTC function.
Program Store Enable:
The read strobe to external program memory. When
executing code from the external program memory, #PSEN
is activated twice each machine cycle, except that two
#PSEN activations are skipped during each access to
external data memory. #PSEN is not activated during
fetches from internal program memory.
X32IN: The 32.768KHz crystal input for RTC
function.
External Access Enable:
#EA must be externally held low to enable the device to
fetch code from external program memory locations. If #EA
is held high, the device executes from internal program
memory.
Crystal 1:
Input to the inverting oscillator amplifier and input to the
internal clock generator circuits.
Crystal 2:
Output from the inverting oscillator amplifier.
8-Bits Micro-controller
With 64KB Flash ROM & 1KB RAM & RTC & ADC & PWM & PDWU embedded
ALE/X32OUT
30
27
33
#PSEN/X32IN
29
26
32
#EA
31
29
35
X1
X2
19
18
15
14
21
20
Specifications subject to change without notice contact your sales representatives for the most recent information.
5
Ver 2.1 SM89S16R1 08/2006
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
