4.10.1. Alphanumeric characters register

This register is used to write characters to the alphanumeric display. The system controller FPGA manages the transfer of character data into a shift register within the alphanumeric display. You must allow each transfer to complete before writing new characters to the display using the following sequence:

  1. Check that the display status is IDLE (bit 0 = 0) in the LED_ALPHA register.

  2. Write 2 characters LED_ALPHA register (as a single 32-bit write to bits [31:1]).

Note

The data from the LED_ALPHA register is transferred as a serial bit-stream into the alphanumeric display at the same time as the LED control bits in LED_LIGHTS register.

Table 4.23 describes LED_ALPHA register bits.

Table 4.23. LED_ALPHA bit assignment

Bit

Name

Function

[30:1]

CHARACTERS

Bit patterns that form characters on the alphanumeric display. See Table 4.24 for segment and bit assignments.

Ensure that the display is idle before writing each new character.

[0]

STATUS

This is a read-only bit that returns the status of the alphanumeric display. For compatibility with the Integrator/AP, this always returns 0.

The digits and segments are identified in Figure 4.21.

Figure 4.21. Identifying the alphanumeric display segment s

The bit assignments for the alphanumeric display segments in the LED_ALPHA register are shown in Table 4.24.

Table 4.24. LED_ALPHA bit-to-segment mapping

Digit 1

Segment

Digit 2

29

DP

30

28

T

14

27

S

13

26

R

12

25

N

11

24

M

10

23

K

9

22

H

8

21

G

7

20

F

6

19

E

5

18

D

4

17

C

3

16

B

2

15

A

1

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