CMD-12DP512 AXIOM, CMD-12DP512 Datasheet - Page 14

• Manufacturer Part Number: CMD-12DP512
• Description: Single Board Computer
• Manufacturer: AXIOM

Specifications of CMD-12DP512

• Silicon Manufacturer: Freescale
• Core Architecture: HCS12
• Core Sub-architecture: S12D
• Features: Onboard Back Ground Debug, Breadboard And Prototype Area
• Kit Contents: Board
• Silicon Family Name: S12D
• Silicon Core Number: MC9S12DP512

C M D - 1 2 D P 5 1 2
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 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 pin out for a dual row rear mounted display
connector.
module type should be TN (Standard Twist) style and Reflective to support this VEE potential.
The Axiom 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
NOTES:
1) The LCD write requires 3 SPI transfers. Transfer 1 provides data 0 - 3 and RS (register
2) CUT-AWAY 1 and 2 provide a means to isolate the LCD Port from the HCS12 SPI channel.
CUT-AWAY options allow the user to disconnect dedicated HCS12 I/O port resources from development board
peripherals. The CUT-AWAY options also allow for establishing the connection again by installing surface mount
0805 size 0 ohm resistors or mod wire with the use of a soldering iron. Normal operation of the development
board generally does not require any manipulation of the CUT_AWAY options.
#1 Cut-Away: HCS12 Port S5/MOSI signal to the LCD_PORT shift register.
#2 Cut-Away: HCS12 Port S7/SS0 signal to the LCD_PORT shift register.
CONTRAST
The contrast adjust potentiometer will provide a -5V to +5V potential for LCD contrast.
LCD_EN Option
The LCD_EN option IN provides the SPI-0 SS* (port PS7) select signal to the on-board LCD
port. The select signal enables the LCD Port operation. With LCD_EN Open or Idle the LCD
port will be disabled and SPI-0 SS* signal (PS7) may be applied to other applications.
DB1
DB3
DB5
DB7
+5V
RS
EN
select) value. Transfer 2 provides the same data with the EN (D7) bit set. Transfer 3
provides same data with the EN bit clear. See the KLCD examples for operation.
10
12
14
2
4
6
8
The LCD module VEE or contrast potential is 0 Volts on this board. The LCD
11
13
1
3
5
7
9
R E V
GND
CONTRAST
R/W-GND
DB0
DB2
DB4
DB6
B .
SPI data bit definitions to LCD Port:
D0 - D3 = DB4 - 7, LCD data
D4 - D5 = Spare pins S1 and S2, not connected
D6 = RS, 0 = LCD Command, 1 = LCD Data
D7 = EN, 1 = LCD enable.
DB0 –DB3 are not applied and have 10K pull-down
resistance.
14
0 8 / 2 3 / 0 7