Motorola CML12S-DP256, MC9S12DP256 manual P1 P4 HCS12 Header Ring, Lcdport Connector

C M L 1 2 S D P 2 5 6 0 7 / 1 7 / 0 2

CAN BUS TERMINATION

The CAN port provides RC11,12, and 13 1206 SMT size termination resistors on the bottom of the CML12Sxxx board that are not installed at the factory. The termination resistors provide optional bias and termination impedance for the CAN bus connected to the CAN Port. Type of wire media, data rate, length of wire, and number of CAN bus nodes can all effect the requirement or value of the termination for the CAN bus. User should refer to particular application for termination requirements.

RC11 CAN-H Bias Resistor: Provides bias to ground potential.

RC12 CAN-L Bias Resistor: Provides bias to +5V potential.

RC13 CAN Termination Resistor: Provides end point termination between CAN-H and CAN-

L signal.

P1 - P4 HCS12 Header Ring

P1 - P4 provide a header ring for all I/O of the HCS12 device. These connectors are not installed. User should refer to the CML12S board schematic diagram for connector pin connections. All HCS12 I/O is available from the other I/O Ports on the board.

LCD_PORT

The LCD_PORT interface is connected to the HCS12 SPI-0 port and applies a serial shift register to convert the data to parallel interface for LCD input. This is required due to the fast timing characteristics of the HCS12 data bus and the slow timing of the standard LCD Modules. Example LCD Port assembly language driver software is provided on the support CD to demonstrate typical LCD module operation using this technique.

The interface supports all OPTREX™ DMC series and similar displays with up to 80 characters in 4 bit bus mode and provides the most common pinout for a dual row rear mounted display connector. The LCD module VEE or contrast potential is 0 Volts on this board. The LCD module type should be TN (Standard Twist) style and Reflective to support this VEE potential. The Axiom Mfg. HC-LCD is also compatible. The LCD Module is configured in a Write only mode, it is not possible to read current cursor position or the busy status back from the module.

LCD_PORT Connector
+5V	2	1	GND	SPI data bit definitions to LCD Port:
RS	4	3	VEE-GND	D0	- D3	= DB4 - 7, LCD data
EN	6	5	R/W-GND	D4	- D5	= Spare pins S1 and S2, not connected
DB1	8	7	DB0	D6	= RS, 0 = LCD Command, 1 = LCD Data
DB3	10	9	DB2	D7	= EN, 1 = LCD enable.
DB5	12	11	DB4	DB0 -DB3 are not applied and have 10K pull-down
DB7	14	13	DB6	resistance.

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