CSM-12C32 AXIOM, CSM-12C32 Datasheet - Page 9

• Manufacturer Part Number: CSM-12C32
• Description: MCU MODULE
• Manufacturer: AXIOM

Specifications of CSM-12C32

• Silicon Manufacturer: Freescale
• Core Architecture: HCS12
• Core Sub-architecture: S12C
• Features: Power Selection Jumper, Analog Comparator, SCI/SPI Communications Ports
• Kit Contents: Board, Cables, CD, Power Supply
• Silicon Core Number: MC9S12C32
• Silicon Family Name: S12C

C S M 1 2 C 3 2
U S E R
Communications
The CSM12C32 module provides a single RS-232 communications port. An RS-232 trans-
ceiver (U2) provides RS-232 signal level to TTL/CMOS logic level translation. RS232 signals
TXD and RXD are routed between the transceiver and the MCU. These signals are also
routed to connector J1. RS-232 communication signals input on J1 must be TTL/CMOS logic
levels; no translation support is provided through this path. The transceiver output may also
be driven off-module if the signals are suitably buffered. As added development support,
hardware flow control signals RTS and CTS are available on the logic side of U2. These sig-
nals are routed to vias located near the transceiver (U2). RTS has been biased properly to
support 2-wire RS-232 communications.
Use of the J1 connector to input RS-232 signals requires disabling the on-board RS-232 trans-
ceiver. Otherwise, signal corruption may occur. Disabling the on-board transceiver is accom-
plished by opening cut-traces CT4, and CT5. Simply remove the circuit trace between the cut-
trace pads to open the circuit. To restore the circuit functionality, install a 1206 size, 0-ohm,
resistor or a short piece of wire across the cut-trace pads.
Table 1: Serial COM Signals
COM Connector
A standard 9-pin Dsub connector provides external connections for the COM port. The COM
port is configured as a DCE device. Component U2 provides RS-232 translation services.
Figure 2 below shows the DB9 connector pin-out.
Figure 2: COM Connector
Connector J1
Connector J1 provides access to CSM12C32 I/O port signals.
G U I D E
RXD
TXD
GND
4, 6
1, 6
1
2
3
4
5
COM Signal
6
7
8
9
TXD
RXD
1, 4
RTS
CTS
NC
Female DB9 connector that interfaces to the DCE serial port via an
RS232 transceiver. It provides simple 2-wire asynchronous serial com-
munications without flow control. A straight-through serial cable may be
connected to a DTE device such a PC
Pins 1, 4, and 6 are connected together.
MCU Port
PS0/RXD
PS1/TXD
9
Connector
J1-5
J1-7
Disable
CT5
CT4
A U G U S T
1 ,
2 0 0 8