Hitachi H8S/2628 Hardware Manual page 336

Bit Bit Name
1 CKE1
0 CKE0
Legend
X: Don't care
Rev. 1.0, 09/02, page 300 of 568
Initial Value R/W
0 R/W
0 R/W
Description
Clock Enable 0 and 1
Selects the clock source and SCK pin function.
Asynchronous mode
00: Internal baud rate generator
SCK pin functions as I/O port
01: Internal baud rate generator
Outputs a clock of the same frequency as the bit
rate from the SCK pin.
1X: External clock
Inputs a clock with a frequency 16 times the bit
rate from the SCK pin.
Clocked synchronous mode
0X: Internal clock (SCK pin functions as clock
output)
1X: External clock (SCK pin functions as clock
input)