STC5428 Datasheet, PDF (59/66 Pages) Connor-Winfield Corporation – Synchronous Clock for SETS

MCLK_Freq_Reset, 0x7F (R/W)
STC5428
Synchronous Clock for SETS
DATASHEET
Register Writes:
Address
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
0x7F
External oscillator frequency selection
Select accepted frequency of MCLK input by writing the associated value to this register three times consecu-
tively, with no intervening read/writes from/to other register. The associated values for the four accepted fre-
quency (10MHz, 12.8MHz, 19.2MHz, 20MHz) are as shown in table below. Three times of consecutive writes
will trigger internal soft-reset. Initial default accepted frequency for STC5428 is 12.8MHz. The accepted fre-
quency of MCLK input returns to 12.8MHz following any regular reset.
Perform writes at least 50us after the regular reset has done.
Associated written values are shown below:
Bit 7 ~ 0
0x11
0x22
0x44
0x88
External Oscillator Frequency Selection
10MHz
12.8MHz
19.2MHz
20MHz
Register Read:
Address
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
0x7F
FRQID
COUNT
ID_Written_Value
This register allows the user read back three values as follows:
FRQID
Indicates the ID of the frequency of MCLK that the STC5428 currently accept. Constant 1 can be read from
FRQID initially since the default accepted frequency for the STC5428 is 12.8MHz. The value of FRQID can
only be updated when three consecutive valid writes are written to the register MCLK_Freq_Reset completely.
Bit 7 ~ 6 FRQID
0
1
2
3
MCLK Frequency
10MHz
12.8MHz
19.2MHz
20MHz
COUNT
Indicates how many times this register has been written to. COUNT is set to 1 when each time a different valid
associated value is written to for the first time and is clear to 0 after three times valid writes are completed.
As described above in Register Writes, the associated value should be written to this register three times con-
secutively, with no intervening read/writes from/to other register. If the written value is invalid or the consecutive
Page 59 of 66
Preliminary
Rev: 0.2
© Copyright the Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Date: April 3, 2014