3-64 Computer Group Literature Center Web Site
System Memory Controller (SMC)
3
I2C Clock Prescaler RegisterI2_PRESCALE_VAL I2_PRESCALE_VAL is a 16-bit register value that will be used in the following formula for calculating frequency of the I2C gated clock signal:I2C CLOCK = SYSTEM CLOCK/ (I2_PRESCALE_VAL +1)/2After power-up, I2_PRESCALE_VAL is initialized to $1F3 which produces a 100 KHz I2C gated clock signal based on a 100.0 MHz system clock. Writes to this register will be restricted to 4-bytes only.I2C Control Registeri2_start When set, the I2C master controller generates a start sequence on the I2C bus on the next write to the I2C Transmitter Data Register and clears the i2_cmplt bit in the I2C Status Register. After the start sequence and the I2C Transmitter Data Register contents have been transmitted, the I2C master controller will automatically clear the i2_start bit and then set the i2_cmplt bit in the I2C Status Register.
Address $FEF80090
Bit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Name I2_PRESCALE_VAL
Operation READ ZERO READ ZERO READ/WRITE
Reset X X $01F3 P
Address $FEF80098
Bit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Name
0
0
0
0
i2_start
i2_stop
i2_ackout
i2_enbl
Operation READ ZERO READ ZERO READ ZERO
R
R
R
R
R/W
R/W
R/W
R/W
Reset XXX
X
X
X
X
0 PL
0 PL
0 PL
0 PL