Rainbow Electronics AT89C51SND1C - Manual (Page 11)

11
AT8xC51SND1C
4109E–8051–06/03
Internal Pin Structure Table 15. Detailed Internal Pin Structure
Notes: 1. For information on resistors value, input/output levels, and drive capability, refer to
the Section “DC Characteristics”, page 181.
2. When the Two Wire controller is enabled, P
1
, P
2
, and P
3
transistors are disabled
allowing pseudo open-drain structure.
3. In Port 2, P
1
transistor is continuously driven when outputting a high level bit address
(A15:8).
Circuit (1) Type Pins
Input TST
Input/Output RST
Input/Output
P1 (2)
P2 (3)
P3
P4
P53:0
Input/Output
P0
MCMD
MDAT
ISP
Output
ALE
SCLK
DCLK
DOUT
DSEL
MCLK
Input/Output
D+
D-
R
TS
T
VDD
R
RS
T
VSS
P
VDD
Watchdog Output
P
3
VSS
N
P
1
VDD VDD 2 osc
Latch Output
periods
P
2
VDD
VSS
N
P
VDD
VSS
N
P
VDD
D+
D-