SAB80C515A-5 Datasheet, PDF (62/108 Pages) Siemens Semiconductor Group – 8-Bit CMOS Single-Chip Microcontroller Family

SAB 80C515A/83C515A-5
Pin Definitions and Functions (cont’d)
Symbol Pin
Pin
Input (I) Function
P-LCC-68 P-MQFP-80 Output (O)
EA
51
49
I
P0.0-P0.7 52-59
52-59
I/O
P5.7-P5.0 60-67
60-67
I/O
HWPD 68
69
I
V_CC
37
V_SS
38
N.C.
–
32, 33
–
34, 35
–
2, 13, 14, 23, –
46, 50, 51,
68, 70, 71
External Access Enable
When held high, the SAB 80C515A executes
instructions from the internal ROM as long as
the PC is less than 32768. When held low, the
SAB 80C515A fetches all instructions from
external program memory. For the SAB
80C515A this pin must be tied low.
Port 0
is an 8-bit open-drain bidirectional I/O port.
Port 0 pins that have 1's written to them float,
and in that state can be used as high-
impedance inputs.
Port 0 is also the multiplexed low-order
address and data bus during accesses to
external program and data memory. In this
application it uses strong internal pullup
resistors when issuing 1's.
Port 0 also outputs the code bytes during
program verification in the SAB 80C515A.
External pullup resistors are required during
program verification.
Port 5 is an 8-bit bidirectional I/O port with
internal pullup resistors. Port 5 pins that have
1's written to them are pulled high by the
internal pullup resistors, and in that state can
be used as inputs. As inputs, port 5 pins being
externally pulled low will source current
(I_IL in the DC characteristics) because of the
internal pullup resistors.
Hardware Power Down
A low level on this pin for the duration of one
machine cycle while the oscillator is running
resets the SAB 80C515A.
A low level for a longer period will force the
part to Power Down Mode with the pins float-
ing. (see table 5)
Supply voltage
during normal, idle, and power-down operation.
Ground (0 V)
Not connected
These pins of the P-MQFP-80 package must
not be connected.
Semiconductor Group
6-10