C541U View Datasheet(PDF) - Siemens AG

Part Name

Description

Manufacturer

C541U

8-Bit CMOS Microcontroller

Siemens AG 

C540U

C541U

Table 2

Pin Definitions and Functions (cont’d)

Symbol

Pin Numbers

I/O*) Function

P-LCC-44 P-SDIP-52

P0.0 - P0.7 44 - 36 50 - 43

I/O 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.

VCCU

1

1

– Supply voltage

for the on-chip USB transceiver circuitry.

VSSU

2

2

– Ground (0V)

for the on-chip USB transceiver circuitry.

VCC

8, 23

10, 26

– Supply voltage

for ports and internal logic circuitry during normal,

idle, and power down mode.

VSS

9, 22

11, 25

– Ground (0V)

for ports and internal logic circuitry during normal,

idle, and power down mode.

*) I = Input

O = Output

Semiconductor Group

11

1997-10-01

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