M35074 Datasheet, PDF (17/44 Pages) Renesas Technology Corp – SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS

MITSUBISHI MICROCOMPUTERS
M35074-XXXSP
SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS
REGISTER SUPPLEMENTARY DESCRIPTION
(1) Setting external clock input and display frequency mode Set-
ting external clock input and display frequency mode (by use of
EXCK0, EXCK1 and DIV11 to DIV0 (12016), as explained here
following.
(a) When (EXCK1, EXCK0) = (0, 0) ...... External clock mode 1
Fosc = 6.3 to 80 MHz (VDD = 4.75V to 5.25V)
Fosc = 6.3 to 40 MHz (VDD = 3.00V to 3.60V)
Input from the TCK pin a constant-period continuous exter-
nal clock that synchronizes with the horizontal synchronous
signal. And input from HOR pin a constant period continu-
ous horizontal synchronous signal.
Never stop inputting the clock while displaying.
Do not have to set a display frequency because the clock just
as it is entered from outside is used as the display clock.
(b) When (EXCK1, EXCK0) = (0, 1) ......Internal clock mode
Fosc = 20 to 120 MHz (VDD = 4.75V to 5.25V)
Clock input from the TCK pin is unnecessary. The multiply
clock of the internally generated horizontal synchronous
signal is used as the display clock.
The display frequency is set by setting the multiply value of
the horizontal synchronous frequency (of the display fre-
quency) in DIV11 to DIV0 (address 12016). Also, set the
display frequency range. (See the next page.)
Display frequency is calculated using the below expression.
Display frequency =Horizontal synchronous frequency ✕
Multiply value
(c) When (EXCK1, EXCK0) = (1, 0) ...... Setting disabled
(d) When (EXCK1, EXCK0) = (1, 1) ...... External clock mode 2
Fosc = 20 to 120 MHz (VDD = 4.75V to 5.25V)
Input from the TCK pin a constant-period continuous exter-
nal clock that synchronizes with the horizontal synchronous
signal. And input from HOR pin a constant-period continu-
ous horizontal synchronous signal.
Never stop inputting the clock while displaying.
An internal clock which is in sync with the external input
clock is used as the display clock.
Because the display frequency equals the external clock
frequency, set N1 (division value) that satisfies the below
expressions to DIV11 to DIV0 (address 12016) for make the
display frequency is equal to the external clock frequency.
Horizontal synchronous signal
External clock
Fig. 3 Example of external clock input
1H
Number of clock (N1)
16