SAH-C515 SIEMENS [Siemens Semiconductor Group], SAH-C515 Datasheet - Page 15

• 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
XTAL2
XTAL1
P2.0-P2.7
PSEN
Semiconductor Group
*) I = Input
O = Output
39
40
41-48
49
Number
P-LCC-
Pin
68
36
37
38-45
47
P-MQFP-
Number
Pin
80
I/O*) Function
–
–
I/O
O
XTAL2
Input to the inverting oscillator amplifier and input to
the internal clock generator circuits.
To drive the device from an external clock source,
XTAL2 should be driven, while XTAL1 is left
unconnected. Minimum and maximum high and low
times as well as rise/fall times specified in the AC
characteristics must be observed.
XTAL1
Output of the inverting oscillator amplifier.
Port 2
is an 8-bit quasi-bidirectional I/O port with internal
pullup resistors. Port 2 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 2 pins being externally pulled low will source
current (I
internal pullup resistors.
Port 2 emits the high-order address byte during
fetches from external program memory and during
accesses to external data memory that use 16-bit
addresses (MOVX @DPTR). In this application it
uses strong internal pullup resistors when issuing
1's. During accesses to external data memory that
use 8-bit addresses (MOVX @Ri), port 2 issues the
contents of the P2 special function register.
The Program Store Enable
output is a control signal that enables the external
program memory to the bus during external fetch
operations. It is activated every six oscillator periods,
except during external data memory accesses. The
signal remains high during internal program
execution.
1-9
IL
, in the DC characteristics) because of the
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C515