Z90251 Datasheet, PDF (62/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
54
Table 35 Master I²C Control Register 0Ch: Bank C (I²C_CNTL)
Bit
7
6
5
4
3
2
1
0
R/W
R/W R/W R/W
Reset
x
x
0
Note: R = Read W = Write X = Indeterminate
R/W
0
R/W
x
R/W
x
R/W R/W
x
x
Bit/
Field
Bit
Position R/W Value Description
Clock Selection
7
R/W
0 1X SCLK for I²C and ADC
1 0.5X SCLK for I²C and ADC
Reserved
I²C Selection 1
I²C Selection 0
6
R
W
Return 1
No Effect
5
R/W 0 P26 selection - POR
P27 selection - POR
1 SCLK1 selection on P26
SDATA1 selection on P27
4
R/W 0 P24 selection - POR
P25 selection - POR
1 SCLK 0 selection on P24
SDATA0 selection on P25
Reserved
3
I²C Enable
2
I²C Speed (for 6-MHz XTAL) 1, 0
R/W
Must be 0
R/W
0 Disable I²C Interface
1 Enable I²C Interface
R/W 00 10 KHz
01 50 KHz
10 100 KHz
11 330 KHz
If bits 4 and 5 both equal 1, then the I²C Selection 0 prevails.
Controlling the I²C Interface
Software controls the I²C module by writing appropriate commands into the I²C
Command Register (I²C_CMD:0Bh:0Ch). See Table 36.
PS001301-0800