Renesas PCA7401 Technické informace stáhnout pdf (Strana 55)

MITSUBISHI MICROCOMPUTERS

M37270MF-XXXSP

M37270EF-XXXSP, M37270EFSP

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER

and ON-SCREEN DISPLAY CONTROLLER

Input

port

(4) Clock for OSD

As a clock for display to be used for OSD, it is possible to select one

of the following 3 types.

•

Data slicer clock output from the data slicer (approximately 26 MHz)

•

Clock from the LC oscillator supplied from the pins OSC1 and OSC2

•

Clock from the ceramic resonator or the quartz-crystal oscillator

from the pins OSC1 and OSC2

This OSD clock for each block can be selected by the following bits

: bit 7 of the port P3 direction register, bits 5 and 4 of the clock source

control register (addresses 0216

16). A variety of character sizes can

be obtained by combining dot sizes with OSD clocks. When not us-

ing the pins OSC1 and OSC2 for the OSD clock I/O pins, the pins

can be used as sub-clock I/O pins or port P6.

Fig. 60. Block diagram of OSD selection circuit

Fig. 59. Structure of clock control register

Table 13. Setting for P6

3/OSC1/XCIN, P64/OSC2/XCOUT

b7 Port P3 direction

Clock source

control register

OSD clock

I/O pin

011

101

Sub-clock

I/O pin

Function

“0”

“11”

“10”

“0”

32 kHZ

Data slicer

circuit

Data slicer clock

OSC1 clock

Ceramic •

quartz-crystal

Oscillating mode for OSD

CS5, CS4

“00”

“1”

CS0

CS1

CS3

CS2 = “0”

CC mode block

OSD mode block

EXOSD mode block

Note : Be sure to set bit 7 to “0” for program of the mask and the

EPROM versions. For the emulator MCU version

(M37270ERSS), be sure to set bit 7 to “1” when using the

data slicer clock for software debugging.

Clock source control register

(CS : address 0216

)

CC mode clock selection bit

0 : Data slicer clock

1 : OSC1 clock

OSD mode clock selection bits

b2 b1

0 0 : Data slicer clock

0 1 : OSC1 clock

1 0 :

1 1 :

Do not set

EXOSD mode clock selection bit

0 : Data slicer clock

1 : OSC1 clock

Pre-divide ratio of layer 2 selection bit

0 : ✕ 1

1 : ✕ 2

Test bit (Note)

OSD1 oscillating mode selection bits

b5 b4

0 0 : 32 kH

oscillating mode

0 1 : Input ports P6

, P6

1 0 : LC oscillating mode

1 1 : Ceramic

•

quartz-crystal

oscillating mode

1 2 ... 50 51 52 53 54 55 56 57 58 59 60 ... 96 97

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Renesas PCA7401 Technické informace Strana 55

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