Specifications
EPSON 10–11
SED1280
SED1280
System Registers
The system registers access the data display RAM,
character generator RAM and LED display RAM. These
write-only registers are addressed using RA0 to RA2 as
shown in the following table.
Address
Name Function
RA2 RA1 RA0
0 0 0 1278 instruction register Sets the 1278 core command and RAM address.
0 0 1 1278 data register Writes to the 1278 character generator RAM and display data RAM.
0 1 0 Not used
1 1 0 Not used
1 0 0 LED address register Sets the LED display register address.
1 0 1 LED data register Writes to the LED display address.
1 1 0 Expanded output port register Controls the expanded output ports.
1 1 1 Test mode register Used for factory inspection prior to delivery.
LED address and data registers
These five, 8-bit registers control an external 5 × 8-LED
display. When a display data bit is set, the corresponding
LED is ON. The following table shows the relationships
LED address register LED data register
Row output pin
DB2 DB1 DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
000 LE1
001 LE2
010 LE3
011 LE4
100 LE5
Column output pin SWS8 SWS7 SWS6 SWS5 SWS4 SWS3 SWS2 SWS1
Note: LED address register bits DB3 to DB7 are ignored.
For example, the following table shows the address and
data sequence to turn ON the two LEDs connected
between LE3 and SW3, and LE3 and SW7.
When LED data is written continuously, the LED address
register increments automatically.
Expanded output port register
This 2-bit register contains the data output on the EO1
and EO2 expanded output ports as shown in the following
table.
Address Data
RA2 RA1 RA0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
1100×××××010
210101000100
Note: × = don’t care
Step
Expanded output port data register
DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
××××××EO2 EO1
Note: × = don’t care
For example, the following table shows the address and
data to set EO1 to LOW and EO2 to HIGH.
Test mode register
This register is used to factory test the SED1280 prior to
delivery. It is initialized by momentarily holding RST
LOW.
Address Data
RA2 RA1 RA0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
110××××××10
Note: × = don’t care
between the registers, the LED output drivers and the
output ports associated with each LED.