83C748 Philips Semiconductors, 83C748 Datasheet - Page 9

• Manufacturer Part Number: 83C748
• Description: 80C51 8-bit microcontroller family 2K/64 OTP/ROM/ low pin count
• Manufacturer: Philips Semiconductors

*
# SFRs are modified from or added to the 80C51 SFRs.
Philips Semiconductors
Table 2.
I/O Port Structure
The 8XC748 has two 8-bit ports (ports 1 and 3) and one 3-bit port
(port 0). All three ports on the 8XC748 are bidirectional. Each
consists of a latch (special function register P0, P1, P3), an output
driver, and an input buffer. Three port 1 pins and two port 0 pins are
multifunctional. In addition to being port pins, these pins serve the
function of special features as follows:
Port Pin
P1.5
P1.6
P1.7
Ports 1 and 3 are identical in structure to the same ports on the
80C51. The structure of port 0 on the 8XC748 is similar to that of the
80C51 but does not include address/data input and output circuitry.
As on the 80C51, ports 1 and 3 are quasi-bidirectional while port 0 is
bidirectional with no internal pullups.
1999 Apr 15
SYMBOL
ACC*
B*
DPTR:
IE*#
P0*#
P1*
P3*
PCON#
PSW*
SP
TCON*#
TL#
TH#
TICON*#
RTL#
RTH#
DPH
DPL
80C51 8-bit microcontroller family
2K/64 OTP/ROM, low pin count
SFRs are bit addressable.
INT0 (external interrupt 0 input)
INT1 (external interrupt 1 input)
T0 (timer 0 external input)
Accumulator
B register
Data pointer
High byte
Low byte
Interrupt enable
Port 0
Port 1
Port 3
Power control
Program status word
Stack pointer
Timer/counter control
Timer low byte
Timer high byte
Timer I control
Timer low reload
Timer high reload
8XC748 Special Function Registers
(2 bytes)
DESCRIPTION
Alternate Function
ADDRESS
DIRECT
D8H/RD
ABH
E0H
F0H
B0H
D0H
8AH
8CH
8BH
8DH
83H
82H
80H
90H
87H
81H
88H
WR
MSB
GATE
EA
CY
DF
E7
F7
AF
T0
B7
D7
8F
97
–
–
–
–
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
INT1
C/T
AE
D6
AC
DE
E6
F6
96
B6
8E
–
–
–
–
–
CLRTI
INT0
AD
DD
9
E5
F5
B5
D5
F0
8D
TF
95
–
–
–
0
Timer/Counter
The 8XC748 has two timers: a 16-bit timer/counter and a 10-bit
fixed-rate timer. The 16-bit timer/counter’s operation is similar to
mode 2 operation on the 80C51, but is extended to 16 bits. The
timer/counter is clocked by either 1/12 the oscillator frequency or by
transitions on the T0 pin. The C/T pin in special function register
TCON selects between these two modes. When the TCON TR bit is
set, the timer/counter is enabled. Register pair TH and TL are
incremented by the clock source. When the register pair overflows,
the register pair is reloaded with the values in registers RTH and
RTL. The value in the reload registers is left unchanged. See the
83C748 counter/timer block diagram in Figure 4. The TF bit in
special function register TCON is set on counter overflow and, if the
interrupt is enabled, will generate an interrupt.
TIRUN
TIRUN
RS1
AC
TR
DC
E4
B4
D4
8C
F4
94
–
–
–
–
RS0
ETI
IE0
AB
DB
E3
F3
B3
D3
8B
93
–
–
–
–
–
EX1
AA
OV
IT0
DA
E2
B2
D2
8A
F2
82
92
–
–
–
–
–
83C748/87C748
ET0
PD
IE1
E1
A9
B1
D1
D9
F1
81
91
89
–
–
–
–
–
Preliminary specification
EX0
IDL
LSB
IT1
E0
F0
A8
B0
D0
D8
80
90
88
P
–
–
–
–
00H
00H
00H
00H
00H
xxxxx111B
FFH
FFH
xxxxxx00B
00H
07H
00H
00H
00H
0000xx00B
00H
00H
RESET
VALUE