83C748 Datasheet, PDF (9/18 Pages) NXP Semiconductors – 80C51 8-bit microcontroller family 2K/64 OTP/ROM, low pin count

Philips Semiconductors
80C51 8-bit microcontroller family
2K/64 OTP/ROM, low pin count
Preliminary specification
83C748/87C748
Table 2. 8XC748 Special Function Registers
SYMBOL
DESCRIPTION
DIRECT
BIT ADDRESS, SYMBOL, OR ALTERNATIVE PORT FUNCTION
ADDRESS MSB
LSB
ACC*
Accumulator
E0H
E7
E6
E5
E4
E3
E2
E1
E0
B*
B register
F0H
F7
F6
F5
F4
F3
F2
F1
F0
DPTR: Data pointer
(2 bytes)
DPH
High byte
83H
DPL
Low byte
82H
RESET
VALUE
00H
00H
00H
00H
IE*#
Interrupt enable
AF
AE
AD
AC
AB
AA
A9
A8
ABH
EA
–
–
–
ETI
EX1
ET0
EX0 00H
P0*#
Port 0
82
81
80
80H
–
–
–
–
–
–
–
– xxxxx111B
P1*
Port 1
P3*
Port 3
97
96
95
94
93
92
91
90
90H
T0 INT1 INT0
–
–
–
–
– FFH
B0H
B7
B6
B5
B4
B3
B2
B1
B0 FFH
PCON# Power control
87H
–
–
–
–
–
–
PD
IDL xxxxxx00B
D7
D6
D5
D4
D3
D2
D1
D0
PSW*
Program status word
D0H
CY
AC
F0
RS1
RS0
OV
–
P 00H
SP
Stack pointer
81H
07H
8F
8E
8D
8C
8B
8A
89
88
TCON*# Timer/counter control
88H
GATE C/T
TF
TR
IE0
IT0
IE1
IT1 00H
TL#
Timer low byte
TH#
Timer high byte
8AH
00H
8CH
00H
DF
DE
DD
DC
DB
DA
D9
D8
TICON*# Timer I control
D8H/RD
–
–
0
TIRUN
–
–
–
– 0000xx00B
WR
–
–
CLRTI TIRUN
–
–
–
–
RTL#
Timer low reload
8BH
00H
RTH#
Timer high reload
8DH
00H
* SFRs are bit addressable.
# SFRs are modified from or added to the 80C51 SFRs.
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
Alternate Function
INT0 (external interrupt 0 input)
INT1 (external interrupt 1 input)
T0 (timer 0 external input)
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.
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.
1999 Apr 15
9