C504 SIEMENS [Siemens Semiconductor Group], C504 Datasheet - Page 10

• Manufacturer Part Number: C504
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Table 1
Pin Definitions and Functions (cont’d)
Symbol
COUT3
EA
P0.0-P0.7
V
V
V
V
*)
Semiconductor Group
AREF
AGND
SS
CC
I = Input
O = Output
28
29
37-30
38
39
16
17
(P-MQFP-44)
Pin Number
I/O
*)
O
I
I/O
–
–
–
–
Function
10-Bit compare channel output
This pin is used for the output signal of the 10-bit compare
timer 2 unit. COUT3 can be disabled and set to a high or
low state.
External Access Enable
When held at high level, instructions are fetched from the
internal ROM (C504-2R only) when the PC is less than
4000 H .When held at low level, the C504 fetches all
instructions from external program memory.
For the C504-L this pin must be tied low.
Port 0
is an 8-bit open-drain bidirectional I/O port. Port 0 pins that
have 1s written to them float, and in that state can be used
as high-impendance inputs.Port 0 is also the multiplexed
low-order address and data bus during accesses to
external program or 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 C504-2R. External pullup resistors are
required during program (ROM) verification.
Reference voltage for the A/D converter.
Reference ground for the A/D converter.
Ground (0V)
Power Supply (+5V)
10
C504