SH7052 datasheet(477/919 Pages) RENESAS

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• Bits 1 and 0—Clock Enable 1 and 0 (CKE1, CKE0): These bits select the SCI clock source

and enable or disable clock output from the SCK pin. Depending on the combination of CKE1

and CKE0, the SCK pin can be used for serial clock output, or serial clock input. Select the

SCK pin function by using the pin function controller (PFC).

The CKE0 setting is valid only in asynchronous mode, and only when the SCI is internally

clocked (CKE1 = 0). The CKE0 setting is ignored in synchronous mode, or when an external

clock source is selected (CKE1 = 1). For further details on selection of the SCI clock source,

see table 14.9 in section 14.3, Operation.

Bit 1:

CKE1

Bit 0:

CKE0 Description*

Asynchronous mode

Internal clock, SCK pin used for input pin (input signal

is ignored) or output pin (output level is undefined)*

Synchronous mode

Internal clock, SCK pin used for synchronous clock

output

Asynchronous mode

Internal clock, SCK pin used for clock output*

Synchronous mode

Internal clock, SCK pin used for synchronous clock

output

Asynchronous mode

External clock, SCK pin used for clock input*

Synchronous mode

External clock, SCK pin used for synchronous clock

input

Asynchronous mode

External clock, SCK pin used for clock input*

Synchronous mode

External clock, SCK pin used for synchronous clock

input

Notes: 1. The SCK pin is multiplexed with other functions. Use the pin function controller (PFC) to

select the SCK function for this pin, as well as the I/O direction.

2. Initial value.

3. The output clock frequency is the same as the bit rate.

4. The input clock frequency is 16 times the bit rate.

SH7052 Datasheet(PDF) 477 Page - Renesas Technology Corp