SAH-C515 SIEMENS [Siemens Semiconductor Group], SAH-C515 Datasheet - Page 16

• Manufacturer Part Number: SAH-C515
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
ALE
EA
P0.0-P0.7
P5.ß-P5.7
N.C.
Semiconductor Group
*) I = Input
O = Output
50
51
52-59
67-60
–
Number
P-LCC-
Pin
68
48
49
52-59
67-60
2, 13, 14,
23, 32, 35,
46, 50, 51,
68, 70, 71
P-MQFP-
Number
Pin
80
I/O*) Function
O
I
I/O
I/O
–
The Address Latch enable
output is used for latching the address into external
memory during normal operation. It is activated
every six oscillator periods, except during an
external data memory access.
External Access Enable
When held high, the C515 executes instructions
from the internal ROM (C515-1R) as long as the
program counter is less than 2000 H . When held low,
the C515 fetches all instructions from ext. program
memory. For the C515-L 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
C515-1R. External pullup resistors are required
during program verification.
Port 5
is an 8-bit quasi-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
internal pullup resistors.
Not connected
These pins of the P-MQFP-80 package must not be
connected.
1-10
IL
, in the DC characteristics) because of the
Introduction
C515