FEDL7055-02

OKI Semiconductor

ML7055

22/30

APPLICATION NOTES

Clock Selection

• The system clock frequency is selected according to external pin SFRQSEL.

SFRQSEL = 0 :

A 13 MHz clock is input to external pins SCLKP.

SFRQSEL = 1 :

A 12 MHz clock is input to external pins SCLKP.

• The CPU clock supply source is selected according to external pin SCLKSEL.

SCLKSEL = 0 :

Use the clock that was divided down from the internal PLL output of 192 MHz that

was generated from external pins SCLKP. (Dividing ratios are selectable in the

range of 1/6 to 1/16. Initial value is 1/8 (24 MHz).)

SCLKSEL = 1 :

Use external pins XC32KP.

Note: The clock supply source can be set by the CLKCNTL register in the CTL/WDT block once the

LSI is powered up.

• The frequency of CPU clock is selectable from the high speed (24 MHz) and low speed (16 MHz). This

can be performed by the Vendor Specific Command.

Setting the Reset

• Apply a “L” level to the

RESET pin for more than 10 µs after power voltage is stabilized. When the

system clock oscillator circuit is stable and the

RESET pin is at a “H” level, the internal reset is released

and operation starts after the internal reset is held for 1.9 ms for the input clock of 13 MHz or 2.0 ms for

the input clock of 12 MHz.

Setting the UART Baud Rate

• It is possible to set the UART baud rate using the Vendor Specific Commands.

Available baud rate settings:

9600/19.2k/38.4k/56k/57.6k/115.2k/230.4k/345.6k/460.8k/921.6k

(Initial value is 115.2 kbps.)

Setting the PCM-CVSD Transcoder

• It is possible to set the PCM-CVSD transcoders using the Vendor Specific Commands.

For command details, contact Oki Electric Industry Co., Ltd.

• It is possible to set the following parameters using the VCCTL command:

- PCMSYNC/PCMCLK mode (initial setting: input)

- Mute reception (initial setting: OFF)

- Mute transmission (initial setting: OFF)

- Air coding

CVSD (initial setting)/

µ-law/A-law

- Interface coding

Linear (initial setting)/

µ-law/A-law

- PCM format (data width of one PCM Linear sample)

8-bit (initial setting)/14-bit/16-bit

- Serial interface format

Short frame (initial setting)/long frame