Fostex G16 - Page 25

3.3.2 Bargraph LED meter lighting section
Although two CPU ’ s, UI (Matsushita) and U2 (NEC) are contained on the Controller, U2
(NEC) functions to light the bargraph LED meter.
1. Dynamic Scan
Lighting is done by dynamic scan. As shown in the drawing below, digit 2 ~ 5 drive the 2
channels of the bargraph LED meter (however, digit 1, 6 ~ 12 drive only the 1 channel of the
bargraph LED meter). The relationship between digit and the assigned channels of the bar 
graph LED meter to be driven are shown in the table 3.2.
And there are 24 segments (12 dot X 2 channels = 24).
Fig. 3.14 Dynamic scan
Table 3.2
digit
1 2
3 4 5
6 7 8 9 10
11 12
assigned
channel
12 1, 13 2, 14
3, 15
4, 16 5
6 7
8
9 10
11
Bargraph lighting pattern is output in LOW/HIGH levels to SEGMENTS 0 ~ 23. The digits
are sequentially switched ON (HIGH output) in order of 1 — >2^.... — *-12 — »-1 — >2 .........
Bargraph LED meter of the channel whose digit is off (LOW output), will not be lit whether
22