DEMO9S08EL32 Freescale, DEMO9S08EL32 Datasheet - Page 10

• Manufacturer Part Number: DEMO9S08EL32
• Manufacturer: Freescale

Specifications of DEMO9S08EL32

• Lead Free Status / RoHS Status: Supplier Unconfirmed

D E M O 9 S 0 8 E L 3 2
U S E R
TIMING
The DEMO9S08EL32 is configured to use the target MCU’s internal clock source by default.
Space is provided for an external, 32 kHz XTAL oscillator; however, the external timing source
is not populated. The internal timing source is active out of RESET. Default configuration sets
the internal bus to run at 8.4MHz. The internal clock source is trimmable to ± 0.2%. Refer to
the MC9S08EL32 Data Sheet for further details.
COMMUNICATIONS
The DEMO9S08EL32 board applies a single Serial Communications Interface (SCI) port
configurable between either SCI or LIN functionality. RS-232 communications are supported
through a DB9 connector. LIN communications are supported through a pair of 4-pin Molex
connectors. A 2x3 option header selects the desired communications protocol.
RS-232
An RS-232 translator provides RS-232 to TTL/CMOS logic level translation on the COM
connector. The COM connector is a 9-pin Dsub, right-angle connector. A ferrite bead on
shield ground provides conducted immunity protection. Communication signals TXD and RXD
are routed from the transceiver to the MCU. Hardware flow control signals RTS and CTS are
available on the logic side of the transceiver. These signals are routed to vias located near the
transceiver.
Table 2 below details the SCI connections to the target MCU.
Table 2: COM Connections
COM Connector
A standard 9-pin Dsub connector provides external connections for the SCI0 port. The Dsub
shell is connected to board ground through a ferrite bead. The ferrite bead provides noise
isolation on the RS-232 connection. Figure 4 below details the DB9 connector pin-out.
Figure 4: COM Connector
G U I D E
MCU Port
PTB1/PIB1/SLTXD/TXD/ADP5
PTB0/PIB0/SLRXD/RXD/ADP4
GND
RXD
TXD
4, 6
1, 6
RTS has been biased properly to support 2-wire RS-232 communications.
1
2
3
4
5
6
7
8
9
1, 4
RTS
CTS
NC
Female DB9 connector that interfaces to the MCU internal SCI0 serial
port via the RS232 transceiver. Flow control is provided at test points on
the board.
Pins 1, 4, and 6 are connected together.
COM Signal
TXD
RXD
10
I/O PORT
CONNECTOR
J1-5
J1-7
A U G U S T
7 ,
2 0 0 8