PT6314 Datasheet, PDF (18/49 Pages) Texas Instruments – 3 Amp Adjustable Positive Step-down Integrated Switching Regulators

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Dot Character VFD Controller/Driver IC
PT6314
TIMING GENERATION CIRCUIT
Timing signals for internal circuit operations(i.e. DDRAM, CGRAM) are generated by the Timing
Generation Circuit. The Display RAM Read timing and the MCU access internal operation timing are
generated separately in order to avoid interferences. Thus, for example, when data is being written to
the DDRAM, no undesirable interference occur (i.e. flickering in areas other than the display location)
VFD DRIVER CIRCUIT
The VFD Driver Circuit is composed of 24 grid and 80 segment signal drivers. During power On, the
character font and number of digits are selected by the hardware (DS0 and DS1), the required grid
signal drivers automatically output drive waveforms while the other grid signal drivers continue to
output non-selected waveforms. The serial data sent is latched when the display data character pattern
corresponding to the last address of the display data RAM (DDRAM). Since the serial data is latched
when the display data character pattern corresponding to the starting address enters the internal shift
register, PT6314 drives from the head display.
CURSOR/BLINK CONTROL CIRCUIT
Cursor and Character blinking are generated by the Cursor / Blink Control Circuit. The cursor or the
blinking will appear with the digit located at the display data RAM (DDRAM) address set in the address
counter (AC).
For example, when the address counter is 08H, the cursor position is displayed at DDRAM Address
08H.
AC6 AC5 AC4 AC3 AC2 AC1 AC0
AC
0
0
0
1
0
0
0
FOR 1-LINE DISPLAY:
Display position
Digit
DDRAM
Address(hexadecimal)
1 2 3 4 5 6 7 8 9 10 11 12
00 01 02 03 04 05 06 07 08 09 0A 0B
FOR 2-LINE DISPLAY:
Display position
Digit
DDRAM
Address(hexadecimal)
Cursor Position
1 2 3 4 5 6 7 8 9 10 11 12
00 01 02 03 04 05 06 07 08 09 0A 0B
40 41 42 43 44 45 46 47 48 49 4A 4B
Cursor Position
Note:
The cursor or blinking appears when the address counter (AC) selects the Character Generator RAM
(CGRAM). The cursor and blinking become meaningless. When the Address Counter is a CGRAM
Address, the cursor or the blinking is displayed in a meaningless position.
PT6314 V1.3
- 18 -
March, 2006