M35070 Datasheet, PDF (17/54 Pages) Mitsubishi Electric Semiconductor – SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS

MITSUBISHI MICROCOMPUTERS
M35070-XXXSP/FP
SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS
REGISTER SUPPLEMENTARY DESCRIPTION
(1) Setting external clock input and display frequency mode
Setting external clock input and display frequency mode (by
use of EXCK0 (12016), EXCK1 (12316) and DIV10 to DIV0
(12016), as explained here following.
(a) When (EXCK1, EXCK0) = (0, 0) ......External synchronous
1 (External clock display) … Fosc = 20 to 70 MHz
Input from the TCK pin a constant-period continuous
external clock that synchronizes with the horizontal
synchronous signal. And input from HOR pin a constant
period continuous 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
synchronous… Fosc = 20 to 90 MHz
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
frequency) in DIV10 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 x
Multiply value
(c) When (EXCK1, EXCK0) = (1, 0) ......… Setting disabled
(d) When (EXCK1, EXCK0) = (1, 1) ......External synchronous 2
(Internal oscillation clock display) … Fosc = 20 to 90 MHz
Input from the TCK pin a constant-period continuous external
clock that synchronizes with the horizontal synchronous
signal. And input from HOR pin a constant-period continuous
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 DIV10 to DIV0 (address 12016) for make the
display frequency is equal to the external clock frequency.
N1 = external clock frequency / horizontal synchronous
frequency
10
N1 = Σ 2nDIVn
n=0
Also, set the display frequency range. (See the next page.)
Horizontal synchronous signal
External clock
Fig. 4 Example of external clock input
1H
Number of clock (N1)
17