ST6280 STMICROELECTRONICS [STMicroelectronics], ST6280 Datasheet - Page 61

• Manufacturer Part Number: ST6280
• Description: 8-BIT OTP/EPROM MCU WITH LCD DRIVER EEPROM AND A/D CONVERTER
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

LCD CONTROLLER-DRIVER (Cont”d)
4.7.3 Stand by or STOP operation mode
No clock from the main oscillator is available in
STOP mode for the LCD controller, and the con-
troller is switched off when the STOP instruction is
executed. All segment and common lines are then
switched to ground to avoid any DC biasing of the
LCD elements.
Operation in STOP mode remain possible by
switching to the OSC32Khz, by setting the
HF0..HF2 bit of LCDCR accordingly
Care must be taken for the oscillator switching that
LCD function change is only effective at the end of
a frame. Therefore it must be guaranteed that
enough clock pulses are delivered before entering
into STOP mode. Otherwise the LCD function is
switched off at STOP instruction execution.
Table 22. Oscillator Source Selection
HF2
0
0
0
1
Others
HF1
0
0
1
1
HF0
0
1
0
1
Clock disabled: Display off
Auxiliary 32kHz oscillator
Reserved
Reserved
Division from MCU f
Division Factor
INT
(Table
22).
4.7.4 LCD Mode Control Register (LCDCR)
Address: DCh - Read/Write
Bits 7-6 = MUX16, MUX11. Multiplexing ratio se-
lect bits . These bits select the number of common
backplanes used by the LCD control.
Bits 5-3 = HF0, HF1, HF2. Oscillator select bits .
These bits allow the LCD controller to be supplied
with the correct frequency when different high
main oscillator frequencies are selected as system
clock.
crystals.
Bits 2 = Reserved.
Bits 1-0 = LF0, LF1. Base frame frequency select
bits. These bits control the LCD base operational
frequency of the LCD common lines.
LF0, LF1 define the 32kHz division factor as
shown in
Table 23. 32kHz Division Factor for Base
Frequency Selection
MUX16 MUX11
LF1
0
0
1
1
0
7
Table 19
LF0
0
1
0
1
0
Table 23
512
386
256
192
128
shows the set-up for different clock
HF2
32kHz Division Factor
HF1
HF0
ST62T80B/E80B
-
LF1
1107
61/78
LF0
0