Rev. 1.0, 02/00, page 876 of 1141
29.11
Character Data ROM (OSDROM) Access by CPU
The character data ROM can be accessed by the CPU as part of user ROM. Before accessing the
character data ROM by the CPU, clear the OSDON bit in the screen control register to 0 to stop
OSD display, then set the OSROME bit in the serial timer register to 1. The character data ROM
can be accessed even in the module stop mode.
If the OSROME bit is set to 1 during OSD display, the character data ROM cannot be accessed
correctly by CPU.
For details on OSROME bit setting, refer to section 29.5.9, Screen Control Register (DCNTL).
29.11.1
Serial Timer Control Register (STCR)
0
0
1
0
2
0
3
0
4
0
5
0
6
0
7
—
OSROME
FLSHE
—
IICX0
IICX1
—
—
R/W
R/W
—
R/W
R/W
—
—
—
0
Bit :
Initial value :
R/W :
Bit 2
OSD ROM Enable (OSROME): Controls the OSD character data ROM (OSDROM)
access. When this bit is set to 1, the OSDROM can be accessed by the CPU, and when this bit is
cleared to 0, the OSDROM cannot be accessed by the CPU but accessed by the OSD module.
Before writing to or erasing the OSDROM in the F-ZTAT version, be sure to set this bit to 1.
Note:
During OSD display, the OSDROM cannot be accessed by the CPU. Before accessing the
OSDROM by the CPU, be sure to clear the OSDON bit in the screen control register to 0
then set the OSROME bit to 1. If the OSROME bit is set to 1 during OSD display, the
character data ROM cannot be accessed correctly by CPU.
Bit 2
OSROME
Description
0
OSDROM is accessed by the OSD
(Initial value)
1
OSDROM is accessed by the CPU