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TS-5400 User's Manual
6.1 DIO Header
The DIO port provides +5V, GND, and 13 digital I/O lines that may
be used to interface the TS-5400 with a wide range of external
devices. DIO lines DIO1_0 thru DIO1_7 are a byte-wide port
accessed at I/O location Hex 7E, while the DIO lines DIO1_8 thru
DIO1_11 and DIO_13 are accessed in the lower 6 bits of I/O
location Hex 7F. I/O location Hex 7D is a control port for the DIO.
The direction of DIO lines DIO1_0 thru DIO1_3 is controlled by bit 0
of I/O location Hex 7D, and the direction of DIO1_4 thru DIO1_7 is
controlled by bit 1 of I/O location Hex 7D. The direction of DIO1_8
thru DIO1_11 is controlled by bit 5 of I/O location Hex 7D, while
DIO1_13 is always an input. In all cases, when a control bit is a "1", it is setting the corresponding DIO
lines to be Outputs, while a "0" sets them to be Inputs. All control bits at I/O location Hex 7D are
initialized at reset to be "0".
When bit 7 of I/O location Hex 7D is a "1", DIO1_13 is connected to IRQ6 allowing this port to trigger an
interrupt.
Pin 12 of the DIO port is an active low reset. If this pin is pulled to ground for more than 1 mS, it will
cause a hard reset to the entire board. It has a 4.7K resistor pull-up to 5V, so a simple switch to ground
can be used.
All digital outputs on this port can source 4 mA or sink 8 mA and the digital inputs have standard TTL
level thresholds and must not be driven below 0 Volts or above 5.0 Volts. DIO lines DIO1_0 thru
DIO1_5 have 4.7KΩ pull-up resistors to 5V biasing these signals to a logic"1".
6.2 Using LCD Port as Digital I/O
The LCD Port can be used as 11 additional digital I/O lines or it can be used to interface to a standard
alphanumeric LCD display. At system reset, the port defaults to DIO mode. If using an LCD display this
port can be switched to LCD mode by writing a "1" into bit 4 at I/O location Hex 7D, or the BIOS call to
enable the LCD also sets bit 4 at I/O location Hex 7D (See Section 7 for LCD mode).
LCD_6
14
13
LCD_7
LCD_4
LCD_5
12
11
LCD_2
LCD_3
10
9
LCD_0
8
7
LCD_1
LCD_WR
LCD_EN
6
5
Bias
4
3
LCD_RS
GND
5V
2
1
Figure 5 – Pinout for LCD header
when used as DIO
at location 7Dh controls the upper 4 bits, pins 11 – 14 in a like manner.
When bit 6 of I/O location Hex 7D is a "1", LCD_RS is connected to IRQ1 allowing this port to trigger an
interrupt.
All digital outputs on this port can source 4 mA or sink 8 mA and the digital inputs have standard TTL
level thresholds and must not be driven below 0 Volts or above 5.0 Volts. LCD_7 and LCD_RS have
4.7KΩ pull-up resistors biasing these signals to a logic"1".
7 LCD Interface
A 14-pin LCD connector is provided on the TS-5400 for interfacing with standard alphanumeric LCD
displays. These displays use a common controller, the Hitachi HD44780 or equivalent. While software
When the LCD port is in DIO mode, pins LCD_RS and LCD_WR are
digital inputs, LCD_EN is a digital output, and LCD_0 thru LCD_7 are
programmable as either inputs or outputs.
LCD_RS and LCD_WR can be read at I/O location 73h bits 7 and 6,
respectively. The state of LCD_EN is controlled by writing to I/O
location 73h bit 0.
LCD_0 thru LCD_7 can be read or written at I/O location 72h. The
direction of this byte-wide port (pins 7 – 14) is determined by bits 2
and 3 at I/O location 7Dh. If bit 2 is a zero, then the lower 4 bits (pins
7 – 10) are inputs. If bit 2 is logic 1, then pins 7 – 10 are outputs. Bit 3
10
Technologic Systems
5 V 16 15 DIO1_7
DIO1_13 14 13 DIO1_6
Reset# 12 11 DIO1_5
DIO1_11 10
9
DIO1_4
DIO1_10
8
7
DIO1_3
DIO1_9
6
5
DIO1_2
DIO1_8
4
3
DIO1_1
GND
2
1
DIO1_0
Figure 2 – DIO1 Header Pinout
10/31/03
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