PIC16F946T-I/PT Microchip Technology, PIC16F946T-I/PT Datasheet - Page 126

• Manufacturer Part Number: PIC16F946T-I/PT
• Description: Microcontroller
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F946T-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 14KB (8K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 336 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MA160011 - DAUGHTER BOARD PICDEM LCD 16F91X
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC16F946
9.8
The LCD timing generation provides an interrupt that
defines the LCD frame timing. This interrupt can be
used to coordinate the writing of the pixel data with the
start of a new frame. Writing pixel data at the frame
boundary allows a visually crisp transition of the image.
This interrupt can also be used to synchronize external
events to the LCD.
A new frame is defined to begin at the leading edge of
the COM0 common signal. The interrupt will be set
immediately after the LCD controller completes
accessing all pixel data required for a frame. This will
occur at a fixed interval before the frame boundary
(T
will begin to access data for the next frame within the
interval from the interrupt to when the controller begins
to access data after the interrupt (T
must be written within T
controller will begin to access the data for the next
frame.
FIGURE 9-17:
DS41265A-page 124
FINT
), as shown in Figure 9-17. The LCD controller
COM0
COM1
COM2
COM3
T
T
FWR
FINT
LCD Interrupts
= T
= (T
(T
FRAME
FWR
FWR
/2 – (2 T
/2 – (1 T
Frame
Boundary
/2*(LMUX<1:0> + 1) + T
(EXAMPLE – TYPE-B, NON-STATIC)
WAVEFORMS AND INTERRUPT TIMING IN QUARTER-DUTY CYCLE DRIVE
FWR
CY
CY
, as this is when the LCD
+ 40 ns))
+ 40 ns))
FWR
minimum = 1.5(T
maximum = 1.5(T
). New data
CY
/2
Preliminary
2 Frames
FRAME
FRAME
Frame
Boundary
/4) – (2 T
/4) – (1 T
When the LCD driver is running with Type-B waveforms
and the LMUX<1:0> bits are not equal to ‘00’, there are
some additional issues that must be addressed. Since
the DC voltage on the pixel takes two frames to maintain
zero volts, the pixel data must not change between
subsequent frames. If the pixel data were allowed to
change, the waveform for the odd frames would not
necessarily be the complement of the waveform
generated in the even frames and a DC component
would be introduced into the panel. Therefore, when
using Type-B waveforms, the user must synchronize the
LCD pixel updates to occur within a subframe after the
frame interrupt.
To correctly sequence writing while in Type-B, the
interrupt will only occur on complete phase intervals. If the
user attempts to write when the write is disabled, the
WERR (LCDCON<5>) bit is set.
Note:
CY
CY
LCD
Interrupt
Occurs
+ 40 ns)
+ 40 ns)
The interrupt is not generated when the
Type-A waveform is selected and when the
Type-B with no multiplex (static) is
selected.
T
FWR
T
FINT
© 2005 Microchip Technology Inc.
Controller Accesses
Next Frame Data
Frame
Boundary
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
3
2
1
0
3
2
1
0
3
2
1
0
3
2
1
0