Philips Semiconductors
80C51 8-bit microcontroller
8K/256 OTP, 8 channel 10 bit A/D, I2C, PWM,
capture/compare, high I/O, low voltage (2.7V–5.5V), low power
SPECIAL FUNCTION REGISTERS
S1ADR
S1DAT
S1STA
S1CON CR2 ENS1 STA ST0 SI
GC DB
DA
0
0
0
D9
AA CR! CR0 D8
PSW
D0
IPO
PS1
B8
IEN0 EA
ES1
AB
P1 P1.7 P1.6
90
80
INTERNAL DATA RAM
7F
BACKUP ORIGINAL VALUE OF NUMBYTMST
53
NUMBYTMST NUMBER OF BYTES AS MASTER
52
SLA SLA+R/W TO BE TRANSMITTED TO SLA
51
HADD HIGHER ADDRESS BYTE INTERRUPT ROUTINE
50
4F
SLAVE TRANSMITTER DATA RAM
STD
48
SLAVE RECEIVER DATA RAM
SRD
40
MASTER RECEIVER DATA RAM
MRD
38
MASTER TRANSMITTER DATA RAM
MTD
30
R1
19
R0
18
00
Figure 46. SIO1 Data Memory Map
SU00978
Preliminary specification
P87C552
1999 Mar 30
50